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CHAPTER 7
NEOPLASIA
CHAPTER 7
NEOPLASIA
PRE LECTURE QUIZ (TRUE/FALSE)
Cancer is a disorder of altered cell differentiation and growth.
Surgery, radiation, and chemotherapy are the only identified treatment modalities for cancer.
The Papanicolaou test is a cytologic method used to detect cancer cells.
Cell differentiation is the process whereby proliferating cells are transformed into different and more specialized cell types.
Benign neoplasms are less differentiated tumors that grow in a crablike manner to invade surrounding tissues, have cells that break loose and travel to distant sites to form metastases, and inevitably cause suffering and death unless their growth can be controlled through treatment.
T
F
T
T
F
PRE LECTURE QUIZ The process of ______________ a tumor involves
the microscopic examination of cancer cells to determine their level of differentiation and the number of mitoses.
In general, benign tumors usually are named by adding the suffix __________ to the parenchymal tissue type from which the growth originated.
The term ________________ is used to describe the development of a secondary tumor in a location distant from the primary tumor.
________________ spread would involve metastasis that occurs by way of the blood vessels.
________________ syndromes are defined as the production of signs and symptoms at sites that are not directly affected by the disease or cancer.
grading
Hematogenic
Metastasis
-oma
Paraneoplastic
NEOPLASIA
Neoplasms proliferate to form new tissue
They do not wait for signals from the body that the new tissue is needed
They ignore signals to stop dividing
They often do not mature normally (differentiate) to do the “job” the tissue is supposed to do
They do not die off (apoptosis) to keep the number of total cells constant
CANCER INCIDENCE AND MORTALITY
THE CELL CYCLE
Normally, the number of cells produced = the number of cells that die
The total number of cells in the body remains constant
GROWTH FACTORS
Cells divide only when they are told to do so by growth factors
These cause stable cells to enter the cell cycle and divide
GROWTH FACTORS (CONT.)
Attach to receptor proteins Which often work by affecting G
proteins Which turn on enzymes (proteins) Which make second messengers Which go down inside the cell and
make it divide
GROWTH FACTOR RECEPTORS
Now this cell is ready to respond to growth factors from another cell
They bind to the receptors and stimulate cell division
PROTO-ONCOGENES
The normal genes that code for normal proteins used in cell division Growth factors Growth factor receptors G proteins Enzymes that produce second
messengers Genes that turn the production of
these proteins on and off
ONCOGENES Oncogenes are mutated proto-
oncogenes They still code for the proteins needed
for cell division But they might produce
Too much of the protein An abnormal protein Protein that turns on all by itself Protein that is made when it is not needed Protein that cannot turn cell division off Protein that should be made by a different
cell
QUESTION
True or False:Oncogenes code for normal proteins
used in cell division.
ANSWER
FalseThe statement describes proto-
oncogenes. Oncogenes are mutated proto-oncogenes that code for abnormal proteins.
G2
M
G1
G0
S
R
Mitosis
Inter-phase
Permanent cell
Cyclin proteins measure whether the cell has grown large enough to divide
Cyclins check that the DNA has been correctly duplicated
Cyclins make sure the cell has made the proteins needed to separate the chromosomes
CHECKPOINTS IN CELL DIVISION
TUMOR-SUPPRESSOR PROTEINS
The checkpoints usually stop the division of mutated cells
They keep most mutations from developing into cancer
So the proteins that control the checkpoints are called tumor-suppressor proteins Cyclins Cyclin-dependent kinases Cyclin inhibitors (p53)
If the genes for these proteins were mutated, you might get many more cancers
CELL DIVISION REQUIRES DUPLICATING THE DNA
Telomeres: DNA sequences at the ends of the chromosomes The enzymes that duplicate DNA
attach here The end of the telomere does not get
duplicated What will happen to the telomere as
the cell continues dividing? A man has a mutation that causes
some of his cells to rebuild their telomeres after every division. Is this a good thing or a bad thing? Why?
ONCOGENESIS
Initiation: Initial mutation occurs
Promotion: Mutated cells are stimulated to divide
Progression: Tumor cells compete with one another and develop more mutations which make them more aggressive
G2
M
G1G0
S
Permanent cell
Stable cell
NORMAL CELLS
Normally, after a cell has divided, it becomes either a permanent cell or a stable cell
These cells stop reproducing and continue working for the body
Labile = Apt or likely to change
DIFFERENTIATION
• “Grown-up” cells are called differentiated because they look different from one another
• You can tell a spleen cell from a skin cell
CELL MUTATION
When differentiated, “working” cells mutate, they form differentiated “working” tumors— benign tumors
When undifferentiated, rapidly dividing cells mutate, they form rapidly dividing tumors—malignant tumors
QUESTION
When a well-differentiated cell mutates, is it more or less likely to become a malignant tumor?
a. Moreb. Lessc. Degree of differentiation has no
bearing on whether a tumor is malignant or benign.
ANSWER
a. Less
The more differentiated a cell is when it mutates, the more likely it is to become a benign tumor. If poorly differentiated cells mutate, the tumor is more likely to become malignant.
NAMING TUMORS
• Benign tumors: tissue name + “-oma”• Glioma - tumor of the brain composed of neuroglia.
• Malignant tumors (cancers)
– Epithelial tissue: tissue name + “carcinoma”– Basal cell carcinoma
– Mesenchymal tissue: tissue name + “sarcoma”– Osteo sarcoma
BENIGN TUMORS
Contain cells that look like normal tissue cells
May perform the normal function of the tissue (like secreting hormones) This may lead to oversecretion
Usually have a capsule around them Usually do not invade neighboring
tissues But they can damage nearby organs
by compressing them
MALIGNANT TUMORS
Contain cells that do not look like normal adult cells
These cells divide rapidly, so: Tumors grow quickly Cells mutate faster and can change
type The tumor does not have clear boundaries
and sends “legs” out into surrounding tissue (the word cancer means “crab” and is based on these crablike legs)
Do not perform the normal functions of the organ May secrete hormones associated with
other tissues Can compress and/or destroy the
surrounding tissues
METASTATIC CARCINOMA IN PERIAORTIC LYMPH NODES
LUNG CANCER
QUESTION
What gross anatomic feature of the lung tumor you just saw makes it likely to be malignant?
a. The tumor is growing quickly.b. The tumor has a poorly defined border.c. Cells do not look like normal cells.d. All of the abovee. b and c
ANSWER
e. b and cGross anatomy can be viewed with the
naked eye. Although rapid growth is a characteristic feature of malignant tumors, this cannot be determined from the slide. However, the lack of a clear border, and the different appearance of the group of cancer cells can be clearly seen.
METASTASIS
Cells in a primary tumor develop the ability to escape and travel in the blood
Imagine you were a cancer cell. What abilities would you need to survive in the tumor?
What abilities would you need to metastasize?
SCENARIO
Mrs. T Has Liver Cancer Her doctor did an initial molecular
diagnosis and put her on targeted therapy; the tumor shrank by almost 75%
Two years later the tumor was growing again, and this time it did not respond to the drug
Last year she was diagnosed with metastases in her femur that has not responded to the drug either
Mrs. T wants to know why the cancer cells stopped responding. Are they not all the same cells?
MANIFESTATIONS OF CANCER
Changes in organ function (organ damage, inflammation, and failure)
Local effects of tumors (e.g., compression of nerves or veins, gastrointestinal obstruction)
Ectopic hormones secreted by tumor cells (paraneoplastic disorders)
Nonspecific signs of tissue breakdown (e.g., protein wasting, bone breakdown)
CHANGES IN ORGAN FUNCTION
Organ failure Benign tumors may cause overproduction of
normal organ secretions Malignant tumors may occasionally cause
overproduction (as in thyroid cancer), but more commonly decrease production of normal organ secretions
QUESTION
Why do malignant tumors usually cause a reduction in the amount of hormones the affected organ produces?
a. Organ damageb. Inflammation of the organc. Organ failured. All of the abovee. a and c
ANSWER
d. All of the aboveEffects of malignant tumors on the organ
system include inflammation and damage, which ultimately lead to organ failure. In all cases the organ cannot function optimally, and is unable to secrete the normal/typical amount of hormones.
LOCAL EFFECTS OF TUMOR GROWTH
Bleeding Compression of blood vessels
Superior vena cava syndrome Portal hypertension
Compression of lymph vessels Edema, ascites, effusion
Compression of hollow organs Compression of nerves
Pain, paralysis
PARANEOPLASTIC SYNDROMES
Cancer cells produce hormones or hormone-like proteins ADH ACTH PTH-related protein
Cancer cells produce proteins that affect clotting Paraneoplastic neurologic disorders
CLINICAL MANIFESTATIONS OF CANCER
Cancer cachexia syndrome Weight loss Muscle wasting Weakness Anorexia Anemia
Cachexia -Greek meaning Bad Condition
TUMOR MARKERS
CANCER TREATMENT
Surgery Radiation Therapy Chemotherapy Hormone and
Antihormone Therapy
Biotherapy
INCIDENCE AND TYPES OF CHILDHOOD CANCER
The incidence of childhood cancers is greatest during the first years of life