Cancer immunotherapy strategies based on overcoming barriers within the tumor microenvironment

COIMMU-1189; NO. OF PAGES 9

Cancer immunotherapy strategies based on overcomingbarriers within the tumor microenvironmentThomas F Gajewski, Seng-Ryong Woo, Yuanyuan Zha,Robbert Spaapen, Yan Zheng, Leticia Corrales and Stefani Spranger

Available online at www.sciencedirect.com

For tumor antigen-specific T cells to effectively control the

growth of cancer cells in vivo, they must gain access to, and

function within, the tumor microenvironment. While tumor

antigen-based vaccines and T cell adoptive transfer strategies

can result in clinical benefit in a subset of patients, most of the

patients do not respond clinically. Even for tumor-infiltrating

lymphocyte (TIL)-based adoptive transfer for patients with

metastatic melanoma, which can provide tumor shrinkage in

around 50% of treated individuals, many patients are not

eligible, in part because there are not sufficient TIL present in

the resected tumor. Thus, the denominator is in fact larger, and

it has been suggested that absence of TIL may be a marker for

poor efficacy of immunotherapies in general. While qualitative

and/or quantitative features of the T cells are important

considerations for efficacy, a major component of primary

resistance likely can be attributed to the tumor

microenvironment. Data are accumulating suggesting that two

major categories of immune resistance within the tumor

microenvironment may exist: failure of T cell trafficking due to

low levels of inflammation and lack of chemokines for

migration, and dominant suppression through immune

inhibitory mechanisms. New therapeutic interventions are

being guided by these observations, and preliminary clinical

success is validating this working model.

Address

University of Chicago, United States

Corresponding author: Gajewski, Thomas F

([email protected] )

Current Opinion in Immunology 2013, 25:xx–yy

This review comes from a themed issue on Cancer immunotherapy:

Clinical translation

Edited by Tom Gajewski and Ton Schumacher

0952-7915/$ – see front matter, Published by Elsevier Ltd.

http://dx.doi.org/10.1016/j.coi.2013.02.009

Introduction: probing the tumormicroenvironment as a predictive biomarkerfor clinical benefit from immunotherapyAnalysis of the tumor microenvironment in a systematic

fashion in patients began with the goal of identifying a

predictive biomarker associated with clinical benefit to

Please cite this article in press as: Gajewski TF, et al.: Cancer immunotherapy strategies based on

dx.doi.org/10.1016/j.coi.2013.02.009

www.sciencedirect.com

therapeutic cancer vaccines. The motivation for this pur-

suit was the observation that vaccine-induced immune

responses as measured in the peripheral blood did not

consistently correlate with anti-tumor activity. In fact, with

the most potent vaccine formulations, the majority of

patients indeed develop antigen-specific T cell responses,

yet only a minority of patients derive clinical benefit [1–4].

In addition, a subset of patients show pre-existing immune

responses against individual tumor antigens, yet they have

detectable growing metastatic disease. Collectively, these

observations pointed toward downstream resistance mech-

anisms at the level of the tumor microenvironment as a

potential explanation for tumor escape.

To begin to address this issue, we performed gene

expression profiling on pre-treatment biopsies from

patients participating in a peptide-based vaccine in

combination with IL-12. Patients were categorized as

having a favorable (CR + PR + SD) or unfavorable (PD)

clinical outcome, and supervised hierarchical clustering

was performed. This analysis revealed a small subset of

genes differentially expressed in the tumors between

these two patient populations. Interestingly, most of

these were genes encoding immunoregulatory factors,

including chemokines and evidence for the presence of

T cells at baseline [5,6]. A similar analysis was extended

to melanoma metastases from 44 additional patients,

which confirmed that this T cell-inflamed phenotype

was present in around 40% of patients [7�]. A similar

result has been observed in a MAGE-3-based vaccine

platform pursued by GSK-Bio, in which a similar T cell-

inflamed tumor microenvironment appeared to correlate

with clinical benefit from their vaccine [8,9]. Interestingly,

a small biomarker study also has been carried out with

melanoma patients being treated with the anti-CTLA-4

mAb ipilimumab. Part of that analysis included gene

expression profiling on pre-treatment biopsies which sim-

ilarly suggested the expression of T cell markers and

chemokine genes in patients who went on to derive clinical

benefit [10,11�]. Although these have all been small studies

and need to be validated prospectively, the results none-

theless suggest that patients in whom a ‘dialogue’ is already

established between the tumor and the host immune

response might be predisposed toward clinical benefit

from active immunization and also from CTLA-4

blockade. A corollary to this notion is that patients with

tumors that lack the ability to recruit activated T cells

may be resistant to these current immunotherapy

approaches [12].

overcoming barriers within the tumor microenvironment, Curr Opin Immunol (2013), http://

Current Opinion in Immunology 2013, 25:1–9



[email protected]


http://www.sciencedirect.com/science/journal/09527915

2 Cancer immunotherapy: Clinical translation


Tumors lacking T cell-based inflammationmay require innate immune triggers topromote T cell traffickingA working model has emerged in which one might envi-

sion the need for a distinct set of immunotherapeutic

interventions dictated by the presence or absence of an

immune-permissive tumor microenvironment. Develop-

ing strategies for how to manipulate non-inflamed tumors

and render them permissive should benefit from a greater

understanding of how a spontaneous T cell response is

able to develop naturally in a subset of patients. Theor-

etically, in addition to the expression of (neo-)antigens

that can be recognized by T cells, the full activation of

such T cells would require innate immune signals that

serve as an endogenous ‘adjuvant’ and properly activate

antigen presenting cells (APCs). For melanoma, the pre-

sence of hundreds of point mutations in coding exons

[13], in addition to the expression of differentiation and

cancer-testis antigens that also have moderate immuno-

genicity, implies an abundance of potential antigens that

should not be rate-limiting. Therefore, it was hypothes-

ized that tumors that do indeed show a spontaneous T

cell-based inflammation may have been the ones that


dx.doi.org/10.1016/j.coi.2013.02.009

Figure 1

T cell-poor tumor

Reasons for imm

Therapeutic int

tumor cell stroma cell macrophage CD8 T ce

Innate immune activationStroma disruption

Manipulation of oncogene singaling pathway

Lack of innate immune activationLack of chemokines

Dense stromaImmunosuppressive oncogene expression

Working model for understanding T cell-inflamed versus non-inflamed tumo

for lack of spontaneous immune responses against a major subset of tumors

as a physical barrier, and a possible contribution of immune suppressive onc

rejection in the cases of T cell-inflamed tumors include extrinsic inhibition by P

by Tregs (right). Therapeutic interventions aiming to overcome many of these

investigated clinically.


successfully engaged critical innate immune pathways.

Clues regarding candidate pathways were gleaned from

our melanoma gene expression profiling analysis, which

revealed the presence of a type I IFN transcriptional

signature in tumors that showed a spontaneous T cell

infiltrate [14�,15]. This result suggested the possibility

that the type I IFN pathway might be upstream from

spontaneous T cell priming against tumor-derived anti-

gens in vivo (Figure 1).

In order to test this notion, mouse models were developed

in which the type I IFN signaling pathway was geneti-

cally ablated in host cells. In fact, knockout mice deficient

in the type I IFN R or the downstream signaling molecule

Stat1 showed markedly reduced priming of T cells

against tumor-associated antigens. This defect mapped

to the level of the host APC compartment, and correlated

with poor accumulation of CD8a+ dendritic cells (DCs) in

the tumor microenvironment. Mixed bone marrow chi-

meras confirmed that type I IFN signaling within the

CD8a+ DC lineage was necessary for maximal T cell

priming against tumors in vivo [15]. Similar results were

obtained by the laboratory of Robert Schreiber using


T cell-inflamed tumor

une evasion

erventions

ll Treg PD-L1 IDO

α-PD-1/PD-L1Treg depletionIDO inhibition

Homeostatic cytokines

Expression of inhibitory factorsT cell anergy

Presence of regulatory immune cells

DAMPs(e.g. DNA)

Current Opinion in Immunology

r microenvironments with implications for therapy. The potential reasons

include failed innate immune activation, the involvement of dense stroma

ogene pathways (left). The potential mechanisms explaining failed tumor

D-L1/PD-1 interactions and IDO, T cell-intrinsic anergy, and suppression

potential barriers have been validated in preclinical models and are being




Modulation of the tumor microenvironment Gajewski et al. 3


completely different model systems [16�]. In those stu-

dies, conditional deletion of the type I IFN R in the

CD11chi compartment also led to poor spontaneous T cell

priming.

If host type I IFN production is critical as part of innate

immune recognition of tumors in vivo, then what is the

major receptor and signaling pathway that drives this

production, and what are the tumor-derived factors that

are sensed by host cells to induced type I IFNs? Several

key pathways have been defined and/or implicated, large-

ly based on pathogen models. These include toll-like

receptors that signal through MyD888 or Trif, cytosolic

RNA sensing via RIG-I and IPS-1, extracellular ATP

sensing through P2X7R, and cytosolic DNA sensing via

p204/IFI16 that forms a complex with STING and leads

to TBK1 activation, IRF3/7 phosphorylation and nuclear

translocation, and IFN-b gene transcription [15,17,18��].Using knockout mice deficient in MyD88, Trif, IPS-1, or

P2X7R we found no evidence for blunting of spontaneous

CD8+ T cell responses against tumor-associated antigens

in vivo. However, STING�/� mice showed a profound

deficiency in the induction of anti-tumor T cell responses

in vivo (Woo and Gajewski, unpublished observations).

These results suggest the possibility that tumor-derived

DNA, presumably liberated from dying tumor cells much

like protein antigens that become cross-presented, might

drive productive APC activation in vivo [19,20]. The

mechanisms of this effect are currently being elucidated.

This model is attractive as it has overlap with the mech-

anisms of induction of some types of autoimmunity such

as lupus, which also involve type I IFNs [21–23].

During the course of these experiments, components of

the inflammasome pathways [24] also have been inter-

rogated. Interestingly, preliminary evidence using in vitromodels has indicated that APCs deficient in specific

inflammasome proteins (e.g. the adapter ASC) show

markedly augmented IFN-b production (Corrales and

Gajewski, unpublished observation). As earlier data had

indicated that type I IFNs could inhibit the inflamma-

some [25�], these results suggest the possibility of a

mutual counter-regulatory loop between the STING

pathway and the inflammasome. The possibility that

negative regulation by components of the inflammasome

or other innate cell-expressed regulatory proteins might

restrict anti-tumor immunity in vivo is currently being

examined.

Together, these observations suggest the possibility that a

major subset of tumors might lack appropriate signals for

innate immune activation that would include type I IFN

production. Therefore, strategies to promote robust

innate signaling via APCs and/or other stromal cells in

the tumor microenvironment might facilitate improved

cross-priming of tumor antigen-specific CD8+ T cells and

also augment chemokine production for subsequent


dx.doi.org/10.1016/j.coi.2013.02.009


effector T cell trafficking, and as a result lead to improved

tumor control. Several such strategies have been explored

in preclinical models and some are being investigated

clinically. The provision of TLR agonists in the tumor

microenvironment, or intratumoral introduction of type I

IFNs, appears to be capable of facilitating chemokine

production and desirable inflammation in the tumor site.

The TNF superfamily member LIGHT can engage the

LTbR on stromal cells and induce chemokine pro-

duction, T cell trafficking, and tumor rejection in vivo[26–28]. Interestingly, high-dose radiation to the tumor

site also appears to induce type I IFN production and to

promote T cell-mediated tumor control [29]. Ultimately,

strategies to increase the frequency of tumor antigen-

specific T cells (such as vaccines) in combination with

interventions to promote improved T cell trafficking into

the tumor microenvironment, will be attractive to pursue

in patients.

One additional consideration for the T cell-poor subset of

tumors is whether lack of T cell-based inflammation

might be explained by the presence of dense sessile

stroma. Evidence suggests that the T cell-poor subset

of tumors may express higher levels of pro-angiogenic

factors. Coukos and colleagues performed gene expres-

sion profiling of vascular endothelial cells in the ovarian

cancer tumor microenvironment and found distinct phe-

notypes associated with the presence or absence of a T

cell infiltrate [30,31]. One of these endothelial cell gene

products, the endothelin B receptor, could be manipu-

lated towards improved T cell trafficking. A high density

of fibroblasts, tumor-supporting macrophages, and extra-

cellular matrix may restrict T cell access. Hans Schrei-

ber’s laboratory has pursued a line of experimentation

demonstrating that tumor cells established in stroma are

much more difficult to reject immunologically as com-

pared to a poorly established tumor cell suspension in

mouse models [32,33]. Interestingly, it may be feasible to

manipulate the stromal composition in solid tumors. In a

pancreatic cancer context, Vonderheide and colleagues

have reported that an agonistic anti-CD40 antibody could

activate macrophages that enter the tumor microenviron-

ment and render the tumors more responsive to che-

motherapy [34]. Whether anti-CD40 may also improve

the effector phase of an anti-tumor T cell response is

actively being investigated.

The underlying molecular mechanisms that explain lack

of spontaneous immune priming and T cell infiltration in

a major subset of melanomas in unclear, but several

hypotheses are being interrogated. This ultimately

becomes a question of inter-patient heterogeneity. First,

it is now apparent that the permutations of oncogenic

signaling pathways that are activated in tumors are not

identical between individual patients, and it is concei-

vable that depending on the given constellation of

mutations, signals that suppress or enhance expression







of immune regulatory genes within the cancer cells may

vary. For example, activated Stat3 has been shown to

block chemokine expression in tumor cell lines [35,36]. If

such pathways are identified then perhaps they could be

targeted with specific inhibitors, so that a dialogue be-

tween the tumor and the host immune response can

become established. Second, it is possible that germline

polymorphisms (presumably in immune regulatory

genes) might regulate thresholds for activation of innate

or adaptive immune cells and thus lead to failure of

spontaneous T cell priming against tumor antigens.

The first example of a gene polymorphism linked to

response to an immunotherapy is the association of a

CCR5 polymorphism with clinical response to high-dose

IL-2 [37]. Interventions that augment activation of rate-

limiting immune activation events governed by these

polymorphisms could then be considered. Third, it is

conceivable that environmental differences may be oper-

ational between patients, in ways that influence systemic

immune capacity. Differences in the composition of

commensal flora have been shown to exert profound

effects on systemic immune responses and the incidence

of autoimmunity [38��]. In addition, exposure to CMV

and the accumulation of high frequencies of CMV-

specific effector/memory CD8+ T cells has been shown

to be associated with poor induction of immune responses

against tumor antigens following active immunization

[39]. If such observations become linked to the apparent

lack of spontaneous anti-tumor immunity in patients,

then manipulation of these immunologically relevant

environmental exposures may become critical.

Tumors that support T cell trafficking appearto show high expression of immunesuppressive pathways that can be targetedtherapeuticallyIf a subset of tumors does indeed support endogenous T

cell priming all the way through to migration of activated

CD8+ effector cells into a chemokine-rich tumor micro-

environment, then it may seem paradoxical that those

tumors exist at all and are not rejected spontaneously by

the host. However, several small functional studies of T

cells isolated from the melanoma tumor microenviron-

ment have suggested that those specific for tumor anti-

gens appear to be hyporesponsive [40–42]. Interestingly,

virus-specific T cells isolated from tumor sites (which are

probably passenger effector cells transiting along chemo-

kine gradients) can be functional, arguing for an antigen-

specific component to this dysfunction [40]. Interrogation

of melanoma metastases by gene expression profiling and

confirmatory assays for candidate immune inhibitory

mechanisms has provided correlative evidence for invol-

vement of at least four important suppressive pathways:

expression of PD-L1/B7-H1, expression of indoleamine-

2,3-dioxygenase (IDO), the presence of infiltrating

CD4+CD25+FoxP3+ regulatory T cells (Tregs), and T

cell-intrinsic anergy [43]. PD-L1/B7-H1 engages the


dx.doi.org/10.1016/j.coi.2013.02.009


inhibitory receptor PD-1 on activated T cells, which

diminishes T cell function [44��]. A large fraction of

TIL expresses PD-1 [45,46], arguing for functional

relevance of this pathway in the tumor microenviron-

ment. IDO is a tryptophan-catabolizing enzyme that was

originally identified as one of the factors involved in

immunologic tolerance at the maternal-fetal interface

[47]. It metabolizes tryptophan to kynurenine, thereby

reducing tryptophan availability and also promoting cel-

lular stress to which T cells are quite sensitive [48]. Tregs

have been shown to increase in number in many cancer

patients and also to be present in tumor sites [49,50].

Anergy is a T cell-intrinsic dysfunctional state that gener-

ally results when the T cell receptor for antigen (TCR) is

ligated in the absence of important costimulatory signals,

most importantly through CD28. The APCs in the tumor

microenvironment, as well as the tumor cells themselves,

usually show low expression of the CD28 ligands B7-1

(CD80) and B7-2 (CD86), arguing in favor of an anergy-

promoting context. We recently have identified the tran-

scription factor EGR2 as a critical regulator of the anergic

phenotype [51]. Conditional ablation of EGR2 in T cells

led to improved immune-mediated tumor control in vivo[51]. Preliminary data have indicated that many CD8+ T

cells infiltrating human melanomas are EGR2+, providing

more direct evidence for a functional contribution of T

cell anergy in tumor immune escape.

Preclinical models of anti-tumor immunity have been

utilized to investigate the therapeutic potential for strat-

egies to interfere with (or reverse) each of these immune

inhibitory pathways. Blocking mAbs against PD-L1, or

the use of PD-1-deficient T cells, can potentiate immune-

mediated tumor control, in some of the models resulting

in complete tumor rejection [52–54]. Small molecule

inhibitors of IDO enzymatic activity can slow tumor

growth in a T cell-dependent fashion [55,56]. Depletion

of Tregs has been achieved either by administering anti-

CD25 mAbs or the use of an IL-2-diptheria toxin fusion

protein, or by ex vivo depletion from T cells with anti-

CD25 beads before adoptive transfer [57–59]. Each of

these can partially control tumor growth in various models

in vivo. For T cell anergy, it had been shown that

transfection of tumor cells to express B7-1 could support

rejection of tumors that normally grow progressively [60–62]. However, this approach has been less effective with

established tumors [63]. Alternatively, reversal of anergy

in vitro can be achieved using cytokines that promote T

cell proliferation via utilization of the gc-containing cyto-

kine receptors [64]. In vivo, the homeostatic cytokines IL-

7 and IL-15 also can have therapeutic activity in tumor

models [65–67], as can adoptive transfer of T cells into

lymphopenic recipients which have liberation of

endogenous IL-7 and IL-15 [59,68–71].

Clinical trials manipulating each of the above immune

inhibitory mechanisms have been initiated in advanced







cancer patients. Arguably the farthest along in clinical

development is the investigation of mAbs that target the

PD-1/PD-L1 axis. Topalian and colleagues recently

reported the results of a phase I/II clinical trial of the

anti-PD-1 mAb developed by Medarex/BMS. A 28%

response rate was observed among the 95 melanoma

patients treated on this study, with many of these

responses being quite durable [72]. Similarly encouraging

results have been reported with an anti-PD-L1 mAb [73].

Preliminary biomarker investigation has suggested that

clinical benefit might be preferentially seen in the subset

of patients having PD-L1 expression and a T cell infil-

trate in the tumor site, arguing again that a T cell-

inflamed tumor microenvironment might serve as a

relevant predictive biomarker. IDO inhibition is being

pursued using small molecule inhibitors. A potent com-

pound developed by Incyte has progressed through phase

I clinical testing and biologically active doses that reverse

the tryptophan/kynurenine ratio have been established.

Phase II studies with this drug have been initiated.

Manipulation of Tregs has largely been attempted via

targeting of CD25. Denileukin diftitox, an IL-2-diptheria

toxin fusion protein, was originally developed as a treat-

ment for CD25+ cutaneous T cell lymphoma [74]. Partial

depletion of Tregs in cancer patients has been seen in

some of the studies, with clinical responses in melanoma

and improved immunogenicity of some vaccines reported

[75–77]. However, not all studies have noted a decrease in

Treg numbers with this approach [78] and the reasons for

differential outcomes are not yet clear. An anti-human

CD25 mAb has also been shown to reduce circulating

Treg numbers in cancer patients [79], and further work

with such Abs is ongoing. Administration of homeostatic

cytokines that may support T cell proliferation and

uncoupling of anergy (in addition to general T cell

expansion) is beginning to be explored. Phase I testing

of IL-7 has identified safe doses that successfully aug-

ment T cell numbers in patients [80,81]. Clinical grade

IL-15 has been produced by the NCI and a phase I study

of intravenous administration has been pursued [82].

While IL-2-like side effects have been observed, T cell

expansion has also been noted. A subcutaneous dose and

schedule also is being evaluated. Interestingly, a phase II

study of IL-21 in melanoma patients has been reported,

and a 22% clinical response rate was observed [83,84].

The mechanism of clinical activity remains to be deter-

mined, but could involve maintenance of anti-tumor T

cell function.

In preclinical models, adoptive transfer of tumor-reactive

T cells into lymphopenic recipients can support homeo-

static proliferation and improved tumor control in vivo[59,68]. This phenomenon occurs through the liberation

of endogenous IL-7 and IL-15, which in turn is capable of

reversing established T cell anergy [70]. It is attractive to

speculate that the successful utilization of lymphopenia-

inducing conditioning regimens for T cell adoptive


dx.doi.org/10.1016/j.coi.2013.02.009


therapy in melanoma patients may, in part, be attributed

to prevention of anergy induction [85,86].

In addition to the inhibitory receptor PD-1 that can blunt

the function of tumor-infiltrating T cells, other negative

pathways have been identified that also appear to be

functionally relevant. Characterization of the EGR2 tran-

scriptome in T cell anergy has identified LAG-3 as one

important target gene (Zheng and Gajewski, unpublished

data). Analysis of tumor-infiltrating T cells has confirmed

the presence of LAG-3 on a major subset, and this re-

ceptor may mark the intrinsically dysfunctional anergic

subpopulation [87,88]. Tim-3 is another inhibitory re-

ceptor that has been shown to be expressed on a subset

of tumor-reactive T cells, both in murine and human

models, and also may mark a dysfunctional subset [89,90].

Blockade of either LAG-3 or Tim-3 has also been shown

to improve the function of anti-tumor T cells in different

model systems, providing a strong rationale for clinical

development of agents targeting these molecules as

immunotherapeutics.

An important consideration for blockade of immune

suppressive pathways is the fact that multiple inhibitory

mechanisms appear to be functioning in concert to shut

down specific T cells in the tumor microenvironment.

Thus, blockade of two or more pathways simultaneously

may be necessary for maximal clinical benefit. Preclinical

data have already shown marked synergy between Treg

depletion and homeostatic proliferation for anergy rever-

sal [59], as well as combined blockade of PD-1 and either

Tim-3 or LAG-3 [90,91]. Preliminary data have addition-

ally suggested synergy between anti-CTLA-4 mAb and

either anti-PD-L1 mAb or IDO inhibition (Spranger and

Gajewski, unpublished observations). Combinations of

anti-CTLA-4 or anti-PD-L1 and strategies to ligate

positive costimulatory receptors, including 4-1BB, also

have been observed to support improved tumor control

preclinically [92]. Therefore, clinical testing of combi-

nation immunotherapies should receive a high priority.

Conclusions and future directionsIncreasing our understanding of the tumor microenviron-

ment has provided a foundation for the rational devel-

opment of immunotherapeutic approaches for the

treatment of cancer. As a T cell-inflamed tumor micro-

environment may be a relevant predictive biomarker for

clinical benefit, novel approaches to induce this pheno-

type as a therapeutic strategy should be pursued. Proof-

of-concept approaches in preclinical models have largely

been evaluated using intratumoral injection, which will

not likely be practical for patients with metastatic cancer.

Therefore, a challenge will be devising technologies for

systemic administration of agents that selectively home to

tumor sites. One attractive approach is the use of tumor-

targeting mAbs that could be coupled with a payload of an

immunomodulatory factor, much in the way cytotoxic







chemotherapeutics have been conjugated to Abs against

HER2 or CD33 [93,94]. While the predictive biomarker

potential of a T cell-inflamed tumor microenvironment

has largely been evaluated in melanoma, it is important to

note that a similar phenotype has been reported in a

variety of solid tumors, including colorectal cancer, renal

cell carcinoma, non-small cell lung cancer, breast cancer,

and ovarian cancer [95,96]. As such, it is an attractive

hypothesis to consider that clinical benefit with immu-

notherapeutic agents might also be observed in the subset

of metastatic patients having this phenotype in other

cancer histologies besides melanoma. While the current

clinical successes with anti-CTLA-4 [97�] and anti-PD-1

[72] mAbs rely on the endogenous T cell response and

what is likely spontaneous T cell priming against tumor

antigens, deliberate increase of anti-tumor T cell fre-

quencies could theoretically act in synergy with blockade

of these or other inhibitory pathways. Thus, combination

studies with potent vaccines or adoptive T cell therapy

should be considered. Finally, while many patients who

show a clinical response to immunotherapies have a

durable clinical benefit, recurrence or progression is none-

theless frequently observed. Understanding the mechan-

isms of secondary resistance ultimately will be critical, in

order to develop the next set of therapeutic to overcome

new barriers that may arise as a result of potent immune

selective pressure.

AcknowledgmentsData discussed in this review were supported by R01CA161005,R01CA127475, R01CA118153, P01CA97296, and the Melanoma ResearchAlliance. Through the course of this work, the authors have appreciated thetechnical support of Michael Leung, Michelle Gao, and Glee Li, as well asinfrastructure support through multiple University of ChicagoComprehensive Cancer Center shared resources (Human ImmunologicMonitoring and cGMP facilities, Functional Genomics Facility, HumanTissue Resource, and Flow Cytometry Facility).

References and recommended readingPapers of particular interest, published within the period of review,have been highlighted as:

� of special interest�� of outstanding interest

1. Peterson AC, Harlin H, Gajewski TF: Immunization with Melan-Apeptide-pulsed peripheral blood mononuclear cells plusrecombinant human interleukin-12 induces clinical activityand T-cell responses in advanced melanoma. J Clin Oncol2003, 21:2342-2348.

2. Fourcade J, Kudela P, Andrade Filho PA, Janjic B, Land SR,Sander C, Krieg A, Donnenberg A, Shen H, Kirkwood JM et al.:Immunization with analog peptide in combination with CpGand montanide expands tumor antigen-specific CD8+ T cellsin melanoma patients. J Immunother 2008, 31:781-791.

3. Adams S, O’Neill DW, Nonaka D, Hardin E, Chiriboga L, Siu K,Cruz CM, Angiulli A, Angiulli F, Ritter E et al.: Immunization ofmalignant melanoma patients with full-length NY-ESO-1protein using TLR7 agonist imiquimod as vaccine adjuvant. JImmunol 2008, 181:776-784.

4. Rosenberg SA, Yang JC, Schwartzentruber DJ, Hwu P,Marincola FM, Topalian SL, Restifo NP, Dudley ME, Schwarz SL,Spiess PJ et al.: Immunologic and therapeutic evaluation of asynthetic peptide vaccine for the treatment of patients withmetastatic melanoma [see comments]. Nat Med 1998, 4:321-327.


dx.doi.org/10.1016/j.coi.2013.02.009


5. Gajewski TF, Meng Y, Harlin H: Chemokines expressed inmelanoma metastases associated with T cell infiltration. 2007ASCO Annual Meeting Proceedings Part I. J Clin Oncol 2007,25:8501.

6. Gajewski TF, Zha Y, Thurner B, Schuler G: Association of geneexpression profile in melanoma and survival to a dendritic cell-based vaccine. J Clin Oncol 2009, 27:9002.

7.�

Harlin H, Meng Y, Peterson AC, Zha Y, Tretiakova M, Slingluff C,McKee M, Gajewski TF: Chemokine expression in melanomametastases associated with CD8+ T-cell recruitment. CancerRes 2009, 69:3077-3085.

This study identified T cell-inflamed melanoma tumor microenvironmentcharacterized by expression of chemokines and other immunomodula-tory genes.

8. Louahed J, Gruselle O, Gaulis S, Coche T, Eggermont AM, Kruit W,Dreno B, Charion Sileni V, Lehmann F, Brichard VG: Expression ofdefined genes identified by pre-treatment tumor profiling:association with clinical responses to the GSK MAGE-A3immunotherapeutic in metastatic melanoma patients. J ClinOncol 2008, 26 (Abstract 9045).

9. Gajewski TF, Louahed J, Brichard VG: Gene signature inmelanoma associated with clinical activity: a potential clue tounlock cancer immunotherapy. Cancer J 2010, 16:399-403.

10. Hamid O, Schmidt H, Nissan A, Ridolfi L, Aamdal S, Hansson J,Guida M, Hyams DM, Gomez H, Bastholt L et al.: A prospectivephase II trial exploring the association between tumormicroenvironment biomarkers and clinical activity ofipilimumab in advanced melanoma. J Transl Med 2011, 9:204.

11.�

Ji RR, Chasalow SD, Wang L, Hamid O, Schmidt H, Cogswell J,Alaparthy S, Berman D, Jure-Kunkel M, Siemers NO et al.: Animmune-active tumor microenvironment favors clinicalresponse to ipilimumab. Cancer Immunol Immunother 2011,61:1019-1031.

This study provided evidence that melanomas with a pre-inflamed tumormicroenvironment may be associated with clinical benefit from anti-CTLA-4 mAb therapy.

12. Gajewski TF: Molecular profiling of melanoma and theevolution of patient-specific therapy. Semin Oncol 2011,38:236-242.

13. Pleasance ED, Cheetham RK, Stephens PJ, McBride DJ,Humphray SJ, Greenman CD, Varela I, Lin ML, Ordonez GR,Bignell GR et al.: A comprehensive catalogue of somaticmutations from a human cancer genome. Nature 2010,463:191-196.

14.�

Fuertes MB, Kacha AK, Kline J, Woo SR, Kranz DM, Murphy KM,Gajewski TF: Host type I IFN signals are required for antitumorCD8+ T cell responses through CD8alpha+ dendritic cells. JExp Med 2011.

See ref. [11�]

15. Fuertes MB, Woo SR, Burnett B, Fu YX, Gajewski TF: Type Iinterferon response and innate immune sensing of cancer.Trends Immunol 2012, 34:67-73.

16.�

Diamond MS, Kinder M, Matsushita H, Mashayekhi M, Dunn GP,Archambault JM, Lee H, Arthur CD, White JM, Kalinke U et al.:Type I interferon is selectively required by dendritic cells forimmune rejection of tumors. J Exp Med 2011, 208:1989-2003.

The above studies identified a key role for host type I IFN signaling viadendritic cells as a critical step in the generation of a natural T cellresponse against tumors in vivo.

17. Barber GN: Innate immune DNA sensing pathways: STING,AIMII and the regulation of interferon production andinflammatory responses. Curr Opin Immunol 2011, 23:10-20.

18.��

Ishikawa H, Ma Z, Barber GN: STING regulates intracellularDNA-mediated, type I interferon-dependent innate immunity.Nature 2009, 461:788-792.

This landmark paper identified the molecule STING as a critical partici-pant in the cytosolic DNA sensing pathway in innate immune recognition.

19. Unterholzner L, Keating SE, Baran M, Horan KA, Jensen SB,Sharma S, Sirois CM, Jin T, Latz E, Xiao TS et al.: IFI16 is an innateimmune sensor for intracellular DNA. Nat Immunol 2010,11:997-1004.







20. Holm CK, Jensen SB, Jakobsen MR, Cheshenko N, Horan KA,Moeller HB, Gonzalez-Dosal R, Rasmussen SB, Christensen MH,Yarovinsky TO et al.: Virus-cell fusion as a trigger of innateimmunity dependent on the adaptor STING. Nat Immunol 2012,13:737-743.

21. Niewold TB, Hua J, Lehman TJ, Harley JB, Crow MK: High serumIFN-alpha activity is a heritable risk factor for systemic lupuserythematosus. Genes Immun 2007, 8:492-502.

22. Gall A, Treuting P, Elkon KB, Loo YM, Gale M Jr, Barber GN,Stetson DB: Autoimmunity initiates in nonhematopoietic cellsand progresses via lymphocytes in an interferon-dependentautoimmune disease. Immunity 2012, 36:120-131.

23. Ahn J, Gutman D, Saijo S, Barber GN: STING manifests self DNA-dependent inflammatory disease. Proc Natl Acad Sci U S A2012, 109:19386-19391.

24. Rathinam VA, Vanaja SK, Fitzgerald KA: Regulation ofinflammasome signaling. Nat Immunol 2012, 13:332-333.

25.�

Guarda G, Braun M, Staehli F, Tardivel A, Mattmann C, Forster I,Farlik M, Decker T, Du Pasquier RA, Romero P et al.: Type Iinterferon inhibits interleukin-1 production and inflammasomeactivation. Immunity 2011, 34:213-223.

This report characterized a cross-inhibitory mechanism between twoinnate immune pathways: the inflammasome and type I IFNs.

26. Yu P, Lee Y, Liu W, Chin RK, Wang J, Wang Y, Schietinger A,Philip M, Schreiber H, Fu YX: Priming of naive T cells insidetumors leads to eradication of established tumors. NatImmunol 2004, 5:141-149.

27. Yu P, Lee Y, Wang Y, Liu X, Auh S, Gajewski TF, Schreiber H,You Z, Kaynor C, Wang X et al.: Targeting the primary tumor togenerate CTL for the effective eradication of spontaneousmetastases. J Immunol 2007, 179:1960-1968.

28. Oh SS, Moon C, Kim DH, Song H, Park S, Fu Y, Kim KD:Adenovirally delivered IFN-beta exerts antitumor effectsthrough transient T-lymphocyte depletion and Ag-specific T-cell proliferation. Int J Mol Med 2012, 29:1153-1157.

29. Burnette BC, Liang H, Lee Y, Chlewicki L, Khodarev NN,Weichselbaum RR, Fu YX, Auh SL: The efficacy of radiotherapyrelies upon induction of type i interferon-dependent innate andadaptive immunity. Cancer Res 2011, 71:2488-2496.

30. Buckanovich RJ, Facciabene A, Kim S, Benencia F, Sasaroli D,Balint K, Katsaros D, O’Brien-Jenkins A, Gimotty PA, Coukos G:Endothelin B receptor mediates the endothelial barrier to Tcell homing to tumors and disables immune therapy. Nat Med2008, 14:28-36.

31. Motz GT, Coukos G: The parallel lives of angiogenesis andimmunosuppression: cancer and other tales. Nat Rev Immunol2011, 11:702-711.

32. Singh S, Ross SR, Acena M, Rowley DA, Schreiber H: Stroma iscritical for preventing or permitting immunological destructionof antigenic cancer cells. J Exp Med 1992, 175:139-146.

33. Zhang B, Zhang Y, Bowerman NA, Schietinger A, Fu YX,Kranz DM, Rowley DA, Schreiber H: Equilibrium between hostand cancer caused by effector T cells killing tumor stroma.Cancer Res 2008, 68:1563-1571.

34. Beatty GL, Chiorean EG, Fishman MP, Saboury B, Teitelbaum UR,Sun W, Huhn RD, Song W, Li D, Sharp LL et al.: CD40 agonistsalter tumor stroma and show efficacy against pancreaticcarcinoma in mice and humans. Science 2011, 331:1612-1616.

35. Niu G, Heller R, Catlett-Falcone R, Coppola D, Jaroszeski M,Dalton W, Jove R, Yu H: Gene therapy with dominant-negativeStat3 suppresses growth of the murine melanoma B16 tumorin vivo. Cancer Res 1999, 59:5059-5063.

36. Burdelya L, Kujawski M, Niu G, Zhong B, Wang T, Zhang S,Kortylewski M, Shain K, Kay H, Djeu J et al.: Stat3 activity inmelanoma cells affects migration of immune effector cells andnitric oxide-mediated antitumor effects. J Immunol 2005,174:3925-3931.

37. Ugurel S, Schrama D, Keller G, Schadendorf D, Brocker EB,Houben R, Zapatka M, Fink W, Kaufman HL, Becker JC: Impact of


dx.doi.org/10.1016/j.coi.2013.02.009


the CCR5 gene polymorphism on the survival of metastaticmelanoma patients receiving immunotherapy. Cancer ImmunolImmunother 2008, 57:685-691.

38.��

Wu HJ, Ivanov II, Darce J, Hattori K, Shima T, Umesaki Y,Littman DR, Benoist C, Mathis D: Gut-residing segmentedfilamentous bacteria drive autoimmune arthritis via T helper 17cells. Immunity 2010, 32:815-827.

This paradigm-shifting study demonstrated that commensal flora couldinfluence a systemic immune response, in this case an autoimmunemodel of arthritis.

39. Solana R, Tarazona R, Aiello AE, Akbar AN, Appay V, Beswick M,Bosch JA, Campos C, Cantisan S, Cicin-Sain L et al.: CMV andimmunosenescence: from basics to clinics. Immun Ageing2012, 9:23.

40. Harlin H, Kuna TV, Peterson AC, Meng Y, Gajewski TF: Tumorprogression despite massive influx of activated CD8(+) T cellsin a patient with malignant melanoma ascites. Cancer ImmunolImmunother 2006, 55:1185-1197.

41. Mortarini R, Piris A, Maurichi A, Molla A, Bersani I, Bono A,Bartoli C, Santinami M, Lombardo C, Ravagnani F et al.: Lack ofterminally differentiated tumor-specific CD8+ T cells at tumorsite in spite of antitumor immunity to self-antigens in humanmetastatic melanoma. Cancer Res 2003, 63:2535-2545.

42. Appay V, Jandus C, Voelter V, Reynard S, Coupland SE, Rimoldi D,Lienard D, Guillaume P, Krieg AM, Cerottini JC et al.: Newgeneration vaccine induces effective melanoma-specificCD8+ T cells in the circulation but not in the tumor site. JImmunol 2006, 177:1670-1678.

43. Gajewski TF: Failure at the effector phase: immune barriers atthe level of the melanoma tumor microenvironment. ClinCancer Res 2007, 13:5256-5261.

44.��

Dong H, Strome SE, Salomao DR, Tamura H, Hirano F, Flies DB,Roche PC, Lu J, Zhu G, Tamada K et al.: Tumor-associated B7-H1 promotes T-cell apoptosis: a potential mechanism ofimmune evasion. Nat Med 2002, 8:793-800.

This was the first study to suggest the PD-L1/B7-H1 expression ontumors could mediate immune escape, leading to the development ofblocking mAbs as a therapeutic.

45. Ahmadzadeh M, Johnson LA, Heemskerk B, Wunderlich JR,Dudley ME, White DE, Rosenberg SA: Tumor antigen-specificCD8 T cells infiltrating the tumor express high levels of PD-1and are functionally impaired. Blood 2009, 114:1537-1544.

46. Chapon M, Randriamampita C, Maubec E, Badoual C, Fouquet S,Wang SF, Marinho E, Farhi D, Garcette M, Jacobelli S et al.:Progressive upregulation of PD-1 in primary and metastaticmelanomas associated with blunted TCR signaling ininfiltrating T lymphocytes. J Invest Dermatol 2011,131:1300-1307.

47. Mellor AL, Sivakumar J, Chandler P, Smith K, Molina H, Mao D,Munn DH: Prevention of T cell-driven complement activationand inflammation by tryptophan catabolism duringpregnancy. Nat Immunol 2001, 2:64-68.

48. Munn DH, Mellor AL: IDO and tolerance to tumors. Trends MolMed 2004, 10:15-18.

49. Curiel TJ, Coukos G, Zou L, Alvarez X, Cheng P, Mottram P,Evdemon-Hogan M, Conejo-Garcia JR, Zhang L, Burow M et al.:Specific recruitment of regulatory T cells in ovarian carcinomafosters immune privilege and predicts reduced survival. NatMed 2004, 10:942-949.

50. Jandus C, Bioley G, Speiser DE, Romero P: Selectiveaccumulation of differentiated FOXP3(+) CD4(+) T cells inmetastatic tumor lesions from melanoma patients comparedto peripheral blood. Cancer Immunol Immunother 2008,57:1795-1805.

51. Zheng Y, Zha Y, Driessens G, Locke F, Gajewski TF:Transcriptional regulator early growth response gene 2 (Egr2)is required for T cell anergy in vitro and in vivo. J Exp Med 2012,209:2157-2163.

52. Dong H, Chen L: B7-H1 pathway and its role in the evasion oftumor immunity. J Mol Med 2003, 81:281-287.







53. Blank C, Brown I, Peterson AC, Spiotto M, Iwai Y, Honjo T,Gajewski TF: PD-L1/B7H-1 inhibits the effector phase of tumorrejection by T cell receptor (TCR) transgenic CD8+ T cells.Cancer Res 2004, 64:1140-1145.

54. Zhang L, Gajewski TF, Kline J: PD-1/PD-L1 interactions inhibitantitumor immune responses in a murine acute myeloidleukemia model. Blood 2009, 114:1545-1552.

55. Uyttenhove C, Pilotte L, Theate I, Stroobant V, Colau D,Parmentier N, Boon T, Van Den Eynde BJ: Evidence for a tumoralimmune resistance mechanism based on tryptophandegradation by indoleamine 2,3-dioxygenase. Nat Med 2003,9:1269-1274.

56. Liu X, Shin N, Koblish HK, Yang G, Wang Q, Wang K, Leffet L,Hansbury MJ, Thomas B, Rupar M et al.: Selective inhibition ofIDO1 effectively regulates mediators of antitumor immunity.Blood 2010, 115:3520-3530.

57. Litzinger MT, Fernando R, Curiel TJ, Grosenbach DW, Schlom J,Palena C: IL-2 immunotoxin denileukin diftitox reducesregulatory T cells and enhances vaccine-mediated T-cellimmunity. Blood 2007, 110:3192-3201.

58. Sutmuller RP, van Duivenvoorde LM, van Elsas A, Schumacher TN,Wildenberg ME, Allison JP, Toes RE, Offringa R, Melief CJ:Synergism of cytotoxic T lymphocyte-associated antigen 4blockade and depletion of CD25(+) regulatory T cells inantitumor therapy reveals alternative pathways forsuppression of autoreactive cytotoxic T lymphocyteresponses. J Exp Med 2001, 194:823-832.

59. Kline J, Brown IE, Zha YY, Blank C, Strickler J, Wouters H, Zhang L,Gajewski TF: Homeostatic proliferation plus regulatory T-celldepletion promotes potent rejection of B16 melanoma. ClinCancer Res 2008, 14:3156-3167.

60. Chen L, Ashe S, Brady WA, Hellstrom I, Hellstrom KE,Ledbetter JA, McGowan P, Linsley PS: Costimulation ofantitumor immunity by the B7 counterreceptor for the Tlymphocyte molecules CD28 and CTLA-4. Cell 1992, 71:1093-1102.

61. Townsend SE, Allison JP: Tumor rejection after directcostimulation of CD8+ T cells by B7-transfected melanomacells [see comments]. Science 1993, 259:368-370.

62. Gajewski TF, Fallarino F, Uyttenhove C, Boon T: Tumor rejectionrequires a CTLA4 ligand provided by the host or expressed onthe tumor: superiority of B7-1 over B7-2 for active tumorimmunization. J Immunol 1996, 156:2909-2917.

63. Fallarino F, Ashikari A, Boon T, Gajewski TF: Antigen-specificregression of established tumors induced by activeimmunization with irradiated IL-12- but not B7-1-transfectedtumor cells. Int Immunol 1997, 9:1259-1269.

64. Boussiotis VA, Barber DL, Nakarai T, Freeman GJ, Gribben JG,Bernstein GM, D’Andrea AD, Ritz J, Nadler LM: Prevention of Tcell anergy by signaling through the gamma c chain of the IL-2receptor. Science 1994, 266:1039-1042.

65. Pellegrini M, Calzascia T, Elford AR, Shahinian A, Lin AE,Dissanayake D, Dhanji S, Nguyen LT, Gronski MA, Morre M et al.:Adjuvant IL-7 antagonizes multiple cellular and molecularinhibitory networks to enhance immunotherapies. Nat Med2009, 15:528-536.

66. Klebanoff CA, Finkelstein SE, Surman DR, Lichtman MK,Gattinoni L, Theoret MR, Grewal N, Spiess PJ, Antony PA,Palmer DC et al.: IL-15 enhances the in vivo antitumor activity oftumor-reactive CD8+ T cells. Proc Natl Acad Sci U S A 2004,101:1969-1974.

67. Epardaud M, Elpek KG, Rubinstein MP, Yonekura AR, Bellemare-Pelletier A, Bronson R, Hamerman JA, Goldrath AW, Turley SJ:Interleukin-15/interleukin-15R alpha complexes promotedestruction of established tumors by reviving tumor-residentCD8+ T cells. Cancer Res 2008, 68:2972-2983.

68. Gattinoni L, Finkelstein SE, Klebanoff CA, Antony PA, Palmer DC,Spiess PJ, Hwang LN, Yu Z, Wrzesinski C, Heimann DM et al.:Removal of homeostatic cytokine sinks by lymphodepletionenhances the efficacy of adoptively transferred tumor-specific CD8+ T cells. J Exp Med 2005, 202:907-912.


dx.doi.org/10.1016/j.coi.2013.02.009


69. Wang LX, Li R, Yang G, Lim M, O’Hara A, Chu Y, Fox BA,Restifo NP, Urba WJ, Hu HM: Interleukin-7-dependentexpansion and persistence of melanoma-specific T cells inlymphodepleted mice lead to tumor regression and editing.Cancer Res 2005, 65:10569-10577.

70. Brown IE, Blank C, Kline J, Kacha AK, Gajewski TF: Homeostaticproliferation as an isolated variable reverses CD8+ T cellanergy and promotes tumor rejection. J Immunol 2006,177:4521-4529.

71. Kline J, Zhang L, Battaglia L, Cohen KS, Gajewski TF: Cellular andmolecular requirements for rejection of B16 melanoma in thesetting of regulatory T cell depletion and homeostaticproliferation. J Immunol 2012, 188:2630-2642.

72. Topalian SL, Hodi FS, Brahmer JR, Gettinger SN, Smith DC,McDermott DF, Powderly JD, Carvajal RD, Sosman JA, Atkins MBet al.: Safety, activity, and immune correlates of anti-PD-1antibody in cancer. N Engl J Med 2012, 366:2443-2454.

73. Brahmer JR, Tykodi SS, Chow LQ, Hwu WJ, Topalian SL, Hwu P,Drake CG, Camacho LH, Kauh J, Odunsi K et al.: Safety andactivity of anti-PD-L1 antibody in patients with advancedcancer. N Engl J Med 2012, 366:2443-2465.

74. Kuzel TM: DAB(389)IL-2 (denileukin diftitox, ONTAK): review ofclinical trials to date. Clin Lymphoma 2000, 1(Suppl. 1):S33-S36.

75. Rasku MA, Clem AL, Telang S, Taft B, Gettings K, Gragg H,Cramer D, Lear SC, McMasters KM, Miller DM et al.: Transient Tcell depletion causes regression of melanoma metastases. JTransl Med 2008, 6:12.

76. Morse MA, Hobeika AC, Osada T, Serra D, Niedzwiecki D,Lyerly HK, Clay TM: Depletion of human regulatory T cellsspecifically enhances antigen-specific immune responses tocancer vaccines. Blood 2008, 112:610-618.

77. Dannull J, Su Z, Rizzieri D, Yang BK, Coleman D, Yancey D,Zhang A, Dahm P, Chao N, Gilboa E et al.: Enhancement ofvaccine-mediated antitumor immunity in cancer patients afterdepletion of regulatory T cells. J Clin Invest 2005,115:3623-3633.

78. Attia P, Maker AV, Haworth LR, Rogers-Freezer L, Rosenberg SA:Inability of a fusion protein of IL-2 and diphtheria toxin(Denileukin Diftitox, DAB389IL-2, ONTAK) to eliminateregulatory T lymphocytes in patients with melanoma. JImmunother 2005, 28:582-592.

79. Rech AJ, Mick R, Martin S, Recio A, Aqui NA, Powell DJ Jr,Colligon TA, Trosko JA, Leinbach LI, Pletcher CH et al.: CD25blockade depletes and selectively reprograms regulatory Tcells in concert with immunotherapy in cancer patients. SciTransl Med 2012, 4:134ra162.

80. Sportes C, Babb RR, Krumlauf MC, Hakim FT, Steinberg SM,Chow CK, Brown MR, Fleisher TA, Noel P, Maric I et al.: Phase Istudy of recombinant human interleukin-7 administration insubjects with refractory malignancy. Clin Cancer Res 2010,16:727-735.

81. Mackall CL, Fry TJ, Gress RE: Harnessing the biology of IL-7 fortherapeutic application. Nat Rev Immunol 2011, 11:330-342.

82. Steel JC, Waldmann TA, Morris JC: Interleukin-15 biology and itstherapeutic implications in cancer. Trends Pharmacol Sci 2012,33:35-41.

83. Thompson JA, Curti BD, Redman BG, Bhatia S, Weber JS,Agarwala SS, Sievers EL, Hughes SD, DeVries TA, Hausman DF:Phase I study of recombinant interleukin-21 in patients withmetastatic melanoma and renal cell carcinoma. J Clin Oncol2008, 26:2034-2039.

84. Petrella TM, Tozer R, Belanger K, Savage KJ, Wong R, Smylie M,Kamel-Reid S, Tron V, Chen BE, Hunder NN et al.: Interleukin-21has activity in patients with metastatic melanoma: a phase IIstudy. J Clin Oncol 2012, 30:3396-3401.

85. Rosenberg SA, Dudley ME: Cancer regression in patients withmetastatic melanoma after the transfer of autologousantitumor lymphocytes. Proc Natl Acad Sci U S A 2004,101(Suppl. 2):14639-14645.







86. Dudley ME, Yang JC, Sherry R, Hughes MS, Royal R, Kammula U,Robbins PF, Huang J, Citrin DE, Leitman SF et al.: Adoptive celltherapy for patients with metastatic melanoma: evaluation ofintensive myeloablative chemoradiation preparativeregimens. J Clin Oncol 2008, 26:5233-5239.

87. Grosso JF, Kelleher CC, Harris TJ, Maris CH, Hipkiss EL, DeMarzo A, Anders R, Netto G, Getnet D, Bruno TC et al.: LAG-3regulates CD8+ T cell accumulation and effector function inmurine self- and tumor-tolerance systems. J Clin Invest 2007,117:3383-3392.

88. Matsuzaki J, Gnjatic S, Mhawech-Fauceglia P, Beck A, Miller A,Tsuji T, Eppolito C, Qian F, Lele S, Shrikant P et al.: Tumor-infiltrating NY-ESO-1-specific CD8+ T cells are negativelyregulated by LAG-3 and PD-1 in human ovarian cancer. ProcNatl Acad Sci U S A 2010, 107:7875-7880.

89. Fourcade J, Sun Z, Benallaoua M, Guillaume P, Luescher IF,Sander C, Kirkwood JM, Kuchroo V, Zarour HM: Upregulation ofTim-3 and PD-1 expression is associated with tumor antigen-specific CD8+ T cell dysfunction in melanoma patients. J ExpMed 2010, 207:2175-2186.

90. Sakuishi K, Apetoh L, Sullivan JM, Blazar BR, Kuchroo VK,Anderson AC: Targeting Tim-3 and PD-1 pathways to reverse Tcell exhaustion and restore anti-tumor immunity. J Exp Med2010, 207:2187-2194.

91. Woo SR, Turnis ME, Goldberg MV, Bankoti J, Selby M, Nirschl CJ,Bettini ML, Gravano DM, Vogel P, Liu CL et al.: Immune inhibitorymolecules LAG-3 and PD-1 synergistically regulate T-cellfunction to promote tumoral immune escape. Cancer Res 2012,72:917-927.


dx.doi.org/10.1016/j.coi.2013.02.009


92. Wang S, Chen L: Immunobiology of cancer therapies targetingCD137 and B7-H1/PD-1 cosignal pathways. Curr Top MicrobiolImmunol 2011, 344:245-267.

93. Sievers EL, Larson RA, Stadtmauer EA, Estey E, Lowenberg B,Dombret H, Karanes C, Theobald M, Bennett JM, Sherman MLet al.: Efficacy and safety of gemtuzumab ozogamicin inpatients with CD33-positive acute myeloid leukemia in firstrelapse. J Clin Oncol 2001, 19:3244-3254.

94. Verma S, Miles D, Gianni L, Krop IE, Welslau M, Baselga J,Pegram M, Oh DY, Dieras V, Guardino E et al.: Trastuzumabemtansine for HER2-positive advanced breast cancer. N Engl JMed 2012, 367:1783-1791.

95. Galon J, Costes A, Sanchez-Cabo F, Kirilovsky A, Mlecnik B,Lagorce-Pages C, Tosolini M, Camus M, Berger A, Wind P et al.:Type, density, and location of immune cells within humancolorectal tumors predict clinical outcome. Science 2006,313:1960-1964.

96. Galon J, Pages F, Marincola FM, Thurin M, Trinchieri G, Fox BA,Gajewski TF, Ascierto PA: The immune score as a new possibleapproach for the classification of cancer. J Transl Med 2012,10:1.

97.�

Hodi FS, O’Day SJ, McDermott DF, Weber RW, Sosman JA,Haanen JB, Gonzalez R, Robert C, Schadendorf D, Hassel JCet al.: Improved survival with ipilimumab in patients withmetastatic melanoma. N Engl J Med 2010.

This clinical trial of ipilimumab in patients with advanced melanomarepresents the first study ever to demonstrate improved overall survivalin this patient population.





Documents

Cancer immunotherapy strategies based on overcoming barriers within the tumor microenvironment