130 Patient with Small Cell Lung Cancer. Bepler, G., Jaques, G., Havemann, K. et al. Department of Internal Medicine,~ Division of Hematology-Oncology, Philipps-University Marburg, 3550 Marburg, Germany. Cancer Res. 47: 1883- 1891, 1987.

Two small cell lung cancer (SCLC) cell lines were established from pericardial and pleural effusions of a patient with histopathologically proven SCLC of the oat cell type. Chemotherapy was administered without response during the 148-day period prior to the establishment of the first cell line. SCLC-22H, and some of the same drugs were administered in the 15 days prior to the establishment of the second cell line, SCLC-21H. Both cell lines dif- fered markedly in their biochemical, kinetic, and morphological properties. Although the biomarkers L-Dopa decarboxylase, bombesin, car- cinoembryonic antigen, and neurotensin were detectable in SCLC-22H, they were undetectable or low in SCLC-21H. The population doubling time was twice as fast and the colony forming ifficiency higher in SCLC-21H than in SCLC-22H. They both expressed high concentrations of the SCLC marker enzymes neuron- specific enolase and the creatine kinase isoenzyme BB and showed no sig- nificant differences in their chromosomal characteristics, c-myc was amplified and expressed in both cell lines, and SCLC-21H had an additional rearranged and amplified EcoRI c-myc fragment. Morphological differences were apparent in liquid culture, cytology, and xenograft histology; SCLC-21H grew much more loosely than SCLC-22H, and had more prominent nucleoli and more abundant cytoplasm. Ultrastructurally dense core granules were present in both cell lines. SCLC- 21H thus expressed properties of the variant cell type of SCLC, whereas SCLC-22H had mixed classic/variant features. An in vivo progression of the patient's tumor from a pure small cell to a mixed small cell/large cell mor- phology could be demonstrated, which suggests that cell line SCLC-22H repre- sents a cell type characteristic for the transitional phase of the tumor. The features of this cell line there- fore define a new subclass of SCLC called transitional cell type. SCLC-22H may be of use to study the mechanism involved in the classic to variant transition, which probably has a con- siderable impact on the prognosis and response to therapy.

Sister Chromatid Exchange Induction by Benzo ( a ) pyrene in Cultured Peripheral Blood Lymphocytes of Lung Cancer Patients and Healthy Individuals With or Without Familial History of

Neoplasms. Dosaka, H., Abe, S., Sasaki, M. et al. First Department of Internal Medicine, Hokkaido University School of Medicine, Hokkaido 060, Japan. Int. J. Cancer 39: 329-332, 1987.

The inducibility of sister chromatid exchanges (SCEs) by benzo(a) pyrene (BP) was studied in cultured peripheral blood lymphocytes of 15 untreated lung cancer patients and 25 healthy persons including ii high- and 14 low-cancer-risk individuals tenta- tively classified by the familial his- tory of lung cancer and other neoplasms. The baseline SCE frequency in cultured lymphocytes was sig- nificantly high in lung cancer patients, as compared with all healthy persons or low-cancer-risk individuals. Following exposure to BP, the lym- phocytes of lung-cancer patients and high-cancer-risk individuals exhibited significantly greater SCE yields than those of persons at low risk, although no significant difference was observed in the lymphocyte SCE yields when the levels of lung cancer patients were compared with those of all healthy persons. A comparison of the net SCE increase (DeltaSCE) in BP-exposed lym- phocytes among the study groups, however, revealed a significant dif- ference in DeltaSCE values only between high- and low-cancer-risk individuals. The present findings on both the ob- served SCE yields and DeltaSCE values suggest that lymphocytes of high-risk individuals may ba more susceptible to BP-induced DNA damage than those of persons at low risk, and that such a chromosomal hypersensitivity to genotoxins may be associated with a high risk of neoplasms.

Radiation Cell Survival and Growth Delay Studies in Multicellular Spheroids of Small-Cell Lung Carcinoma. Duchesne, G.M., Peacock, J.H. Radiotherapy Research Unit, Institute of Cancer Research, Sutton, Surrey SM2 5PX, U.K. Int. J. Radiat. Biol. 51: 365-375, 1987.

The radiation sensitivity of two small-cell lung carcinoma cell lines growing as multicellular spheroids in static culture was determined using clonogenic cell survival and growth delay as endpoints. Growth delay deter- mination suggested that clonogenic cell kill was less than was obtained by direct assay of cell survival. Recovery from potentially lethal damage was as- sayed in one line (HCI2) but was not demonstrable, and clonogenic cell sur- vival decreased with time in treated spheroids with diameters greater than 300 mum which contained a hypoxic cell population. Microscopic examination of the treated spheroids showed the emer-

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gence of an abnormal giant-cell population, and the progressive clonogenic cell loss that occurred after treatment was thought to be due to oxygen and nutrient deprivation of the remaining viable cells by this doomed cell population. Correction of the growth delay measurements for changes in cell size and clonogenic cell population allowed correlation of the growth delay and cell survival data.

A Comparison of Clonogenic and Radionuclide Uptake Assays for Deter- mining the Radiation Response of Human Small-Cell Lung Cancer Xenografts and Cell Lines. Fox, N.E., Twentyman, P.R. Medical Re- search Council Clinical Oncology and Radiotherapeutics Unit, MRC Centre, Cambridge CB2 2QH, U.K. Br. J. Radiol. 60: 381-388, 1987.

Previous work has suggested that a radionuclide (3HTdR) uptake assay can provide a measure of drug and radiation sensitivity comparable with that given by the clonogenic assay. We have now extended this work to examine the radiation response of human small-cell lung cancer xenografts and cell lines with a wide range of plating efficiencies. Preliminary experiments using cultured cells indicated that ir- radiation of a single-cell suspension following disaggregation generally produced similar response data to those obtained when cultures were irradiated in situ and subsequently disaggregated. The response of eight cell lines to a single dose of 2 Gy was measured using both radionuclide uptake and clonogenic assays. There was no correlation be- tween the two sets of data. Agreement between the radiation-response curves obtained using 3HTdR uptake and clonogenic assays was better for high plating efficiency xenografts (NCI-H69, COR-L51) than for low plating ef- ficiency xenografts (COR-L24, COR-L31). Radionuclide uptake indicated very shallow response curves for the low plating efficiency lines. Altering the time of radi~,nuclide addition from the standard Day 4 to other times between Day 2 and Day 6 did not greatly change the indications of radioresponsiveness provided by the assay. Growth-curve ex- periments for line COR-L24 showed that cell numbers at Day 4 after irradiation with 1.5 Gy or 3 Gy were very similar to those in unirradiated cultures. For NCI-H69, however, the cell numbers were very different for the different radia- tion doses. It appears that a high proportion of cells in lines such as COR-L24 take many days to show radia- tion damage as measured by reduced 3HTdR uptake.

Isolation of Small Cell Lung Cancer- Associated Antigen From Human Brain. Watanabe, J.-I., Okabe, T., Fujisawa, M. et al. The Third Department of In- ternal Medicine, Faculty of Medicine, University of Tokyo, Tokyo 113, Japan. Cancer Res. 47: 960-962, 1987.

Previous studies have demonstrated that monoclonal antibody TFS-4 recog- nizes a cell surface antigen with a molecular weight of 124,000 expressed selectively on small-cell lung cancer but not on non-small-cell lung cancers and that is cross-reacts with human brain. The antigenic determinant on small-cell lung cancer and that on brain shared common characteristics, i.e., trypsin sensitivity, heat lability, and neuraminidase resistance, suggesting that they are similar pep- tides (T. Okabe et al., Cancer Res., 44: 5273-5278, 1984; J-i. Watanabe et al., Cancer Res., 47: 826-829, 1987). In order to elucidate the nature of this unique antigen recognized by TFS- 4, we have purified the antigen to homogeneity from human brain. The an- tigen was solubilized from brain with 0.5% Nonidet P-40, precipitated with 50% ammonium sulfate, and subsequently purified by sequential chromatographi- es, i.e., diethylaminoehtyl-Sepharose ion exchange, immunoaffinity, and gel permeation high-pressure liquid chromatography. The antigenic reac- tivity was assessed by immunoblotting using TFS-4 as a primary antibody. The purified antigen showed a single protein band with a molecular weight of 124,000 on sodium dodecylsulfate- polyacrylamide gel electrophoresis detected by a silver staining technique. The results suggest that the antigen on brain tissues is struc- turally related to the molecule expressed on small-cell lung cancer.

Monoclonal Antibody that Distinguishes Small-Cell Lung Cancer From Non-Small- Cell Lung Cancer. Watanabe, J.-I., Okabe, T., Fujisawa, M. et al. The Third Department of In- ternal Medicine, Faculty of Medicine, University of Tokyo, Hongo, Tokyo 113, Japan. Cancer Res. 47: 826-829, 1987.

To examine whether a monoclonal antibody, TFS-4, can distinguish small- cell lung cancer from non-small-cell lung cancers, an extensive survey of fresh lung tumors, cancers from other organs, and normal tissue specimens has been carried out. The antibody has been shown to react specifically with small- cell lung cancer (15 of 15) but not with squamous cell carcinoma (0 of 20), adenocarcinoma (0 of 20) of the lung, or large-cell lung cancer (0 of 2). It reacted neither with other malignancies, including colorectal cancer, gastric cancer, and malignant