The mutagenic compound 2-amino-3-methylimidazo[4, 5-f]quinoline, originally isolated from broiled sardines and also present in cooked beef and beef extract, is being tested for carcinogenicity in F344 rats of both sexes. High incidences of tumors of the Zymbal gland, colon, small intestine and liver in males have been observed in the first 300 days of the experiment.

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Male Syrian golden hamsters were given 1.0% 2-tert- or 3-tert-butylated hydroxyanisole (BHA) or crude BHA for 1 to 4 weeks. The incidence of severe hyperplasia induced in the forestomach was high in the hamsters given 3-tert-BHA or crude BHA for 2 weeks or more, but was almost at the control level in those given 2-tert-BHA. Thus, the 3-tert isomer would appear to be responsible for the tumorigenicity of crude BHA.

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Morris hepatoma 7794A was found to have its c-myc gene amplified 5-to 10-fold. The over-expression of c-myc was observed in all three hepatomas studied (Morris hepatomas 5123D, 7136A and 7794A), although in the first two instances the c-myc genes were not amplified. Over-expression or deregulation of c-myc seems to be a general phenomenon associated with hepatoma.

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Transfusion of 15ml of blood from a rhesus monkey seropositive for human T-cell leukemia virus (HTLV) antigens to an anti-HTLV negative rhesus monkey resulted in the seroconversion of the recipient after five weeks. Cultured peripheral lymphocytes from the seroconverted monkey expressed HTLV antigens and type C virus particles.

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A rabbit lymphoid cell line transformed by human T-cell leukemia virus (HTLV) was inoculated into the peritoneal cavity of six newborn hamsters treated by antilymphocyte serum. All of them developed lethal tumors two weeks after implantation. The tumor cells were chromosomally of rabbit type, and harbored HTLV and HTLV antigens.

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A monoclonal antibody, ST-4-39, was obtained by means of a unique immunization procedure using a gastric cancer xenograft as an immunogen. ST-4-39 reacted immunohistochemically with various cancers and a limited number of normal tissues. The antigen reactive with ST-4-39 was detected in sera of cancer patients, and possessed a molecular weight of _??_1×10⁵. The antigenic determinant was a sialyl-sugar residue different from sialyl-Lewis^a recognized by NS 19-9.

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A short-term study was made for the urinary mutagenicity caused by cigarette smoking in several volunteers. In order to concentrate the mutagens from urine, cotton linked to a copper-phthalocyanine derivative (blue cotton) was used as an adsorbent. The mutagenicity as measured by the Ames test on Salmonella typhimurium TA98 in the presence of S9 increased rapidly after the start of smoking. When smoking was stopped, the activity began to decrease, and after 6 to 13hr reached the non-smoking level. There was no great difference among individuals regarding this time-dependent response. These studies have shown that the appearance and disappearance of mutagenicity in urine in relation to cigarette smoking are rapid processes.

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Sodium chloride, saccharin sodium, phenobarbital sodium and aspirin were tested for tumor-promoting activity in the glandular stomach of rats after initiation with N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) coupled with administration of a high salt diet. Male outbred Wistar rats were given MNNG in the drinking water (100mg/liter) for 8 weeks, and during this period they were fed on diet supplemented with 10% sodium chloride. Thereafter, they were divided into 5 groups and fed on the basal diet or one of various diets supplemented with 10% sodium chloride, 5% saccharin, 0.05% phenobarbital or 1% aspirin until the end of the experiment. All animals were killed at the 40th experimental week for necropsy and histological examination. The incidence of adenocarcinoma was increased in the group given sodium chloride following initiation by MNNG and sodium chloride as compared with the group given MNNG and sodium chloride initiation only, but not significantly. However, the incidence of preneoplastic hyperplasia was significantly increased in this group. Saccharin also enhanced the development of adenocarcinomas of the glandular stomach. The results indicated that dietary administration of sodium chloride or saccharin after MNNG tends to promote tumor development. Phenobarbital or aspirin did not enhance tumor development, aspirin in fact rather showing a tendency to decrease the tumor incidence.

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The organotropic effect of orally administered N-bis(2-hydroxypropyl)nitrosamine (DHPN) in male F344 rats was studied with respect to total dosage and length of observation period. DHPN was given at 5 dosages, a single intragastric intubation of 800mg/kg body weight, or administration as a 0.2% solution in the drinking water for 4, 7, 14 or 21 days. Animals were killed at weeks 32, 40 and 48. Tumors were induced in the lung, thyroid, kidney and urinary bladder. High tumor incidence was demonstrated in the lung and thyroid. Dose-related increases in overall tumor incidences in these 4 organs were clearly shown but time-related increases at the 3 sacrifice time points were not clear. Histologically, the tumors were adenoma and adenocarcinoma of the lung and thyroid, renal cell tumor, nephroblastoma and transitional cell tumor of the kidney, and transitional cell papilloma of the urinary bladder.

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β-Glucuronidase from human lung neoplasms of various histological types and from uninvolved tissues was studied. A significant elevation of β-glucuronidase activity was observed in adenocarcinoma and squamous cell carcinoma of the lung as compared with the corresponding uninvolved tissues (P<0.01). Saccharo-1, 4-lactone, a strong inhibitor of the enzyme, exhibited a substantially greater stabilizing effect on the adenocarcinoma enzyme than on the other enzymes. However, removal of the carbohydrate moiety from the adenocarcinoma enzyme by treatment with endo-β-N-acetylglucosamidase H (endoglycosidase H) brought about a decrease in the stabilizing effect. Tumor β-glucuronidase showed considerable negative charge heterogeneity in the pI range from 4.2 to 6.2 in isoelectric focusing on polyacrylamide gel. Upon treatment with exogenous alkaline phosphatase or endoglycosidase H, the heterogenous variant forms of the tumor enzyme appeared to partly or completely lose their negative charge and to be converted into forms similar to those of the normal lung enzyme. These data strongly suggest that the variants are highly phosphorylated on the oligosaccharide chains of the enzyme. An experiment on the labeling of β-glucuronidase with [³²P]-phosphoric acid provided further evidence that the acidic variants found in lung cancers are extensively phosphorylated forms of the enzyme.

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Leukemia cells from patients with acute myeloid leukemia in relapse were treated with various inducers of differentiation of human myeloid leukemia cell lines. Leukemia cells in primary culture from most, but not all, patients underwent morphological, cytochemical and biochemical changes after treatment with inducers of differentiation such as 12-O-tetradecanoylphorbol-13-acetate (TPA), retinoic acid, actinomycin D, aclarubicin, and alkyl lysophospholipid. The most effective inducer varied from specimen to specimen. Leukemia cells from patients in relapse were compared with those from untreated patients. The responsiveness to TPA of leukemia cells from patients in relapse was similar to that of leukemia cells from untreated patients. However, retinoic acid or actinomycin D resistance was more frequently observed in leukemia cells from patients in relapse than in those from patients before initial therapy. This is the first report to indicate that leukemic cells from relapsed patients who are resistant to cytotoxic chemotherapeutic drugs can be induced to differentiate into mature cells by appropriate inducers. However, the responsiveness to inducers of leukemia cells from patients in relapse is not the same as that of leukemia cells before therapy.

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A human cancer cell line (ZK-1) has been established from a well-differentiated squamous cell carcinoma of the tongue. The cytokeratin polypeptides pattern of ZK-1 cells consists of four major polypeptides with molecular weights between 46 and 58 kilodaltons (kd). Antibodies raised against the purified 58kd cytokeratin filament from cultured ZK-1 cells were shown to be specific by one- and two-dimensional polyacrylamide gel electrophoresis, immunofluorescence, and immunoelectron microscopy. Immunoprecipitation studies showed that the antibody reacted mainly with the 58kd cytokeratin. The distribution of the 58kd cytokeratin in both sparse and confluent cultures was analyzed by the indirect immunofluorescence technique. In both cases, it appeared that fibrillar arrays extended throughout the cytoplasm running over the nucleus and toward cell-to-cell boundaries. Thick bundles of filaments were seen in confluent cultures, especially in large and flattened keratinized cells. Characteristically, reactions were also seen in the intercellular boundaries, appearing as “dots.” Electron microscopy using immunoperoxidase techniques indicated that the 58kd cytokeratin was localized in tonofilaments, tonofilaments attached to desmosomes, desmosomal plaques and membrane-coating granules.

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The aggregating properties of murine melanoma cell lines with low metastatic potential (B16-F1) and high metastatic potential (B16-F10 and B16-BL6) were compared. All three types of cells were found to possess Ca²⁺-dependent and Ca²⁺-independent intrinsic mechanisms for cell adhesion, though the extent of reaggregation varied in each mechanism. After trypsin treatment at around 1μg/ml, F10 and BL6 cells reaggregated in the presence of 1mM Ca²⁺ to a greater degree than F1 cells. F10 and BL6 cells were also more aggregative than F1 cells after dissociation with collagenase. The apparent adhesiveness of the cells was found to be dependent on both the manner of cell preparation for reaggregation and on the presence of external Ca²⁺ or serum factors. The results are discussed in relation to the mechanisms of tumor cell arrest with emphasis on the effect of extracellular factors on cell adhesiveness.

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The distribution of blood group ABH antigens, their precursor I(Ma) antigen, Lewis^a antigen and monoclonal antibody-defined tumor-associated antigen CA 19-9 in gastric cancers and their surrounding non-neoplastic mucosa was studied by using immunohistochemical methods. ABH antigens were localized in the foveolar epithelium except for a few cases presumed to be non-secretors, but ABH antigens were lost focally from metaplastic mucosa. In contrast, Lewis^a and I(Ma) antigens were present in the foveolar epithelium of non-secretors and metaplastic mucosa where ABH antigens were not detected. Gastric cancers also showed focal loss of ABH antigens and gain of Lewis^a and I(Ma) antigens, and the cancer cells showed marked heterogeneity in antigen expression compared with non-neoplastic mucosa. Expression of incompatible blood group antigen (A-like antigen) reactive with monoclonal anti-A antibody was also detected in cancer cells of blood group O and B cases. CA 19-9 (sialylated-Lewis^a) was detected in 62% of gastric cancers and in the restricted areas of gastric mucosa where Lewis^a was positive.

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Vincristine (VCR) combined with interferon (IFN)-β suppressed H. Ep #2 cell proliferation more than additively, whereas 6-mercaptopurine combined with IFN-β suppressed it less than additively. Factors associated with the more-than-additive effect were examined. The enhanced antiproliferation was achieved in HeLa cells as well as H. Ep #2 cells but not in Daudi or M-14 cells, indicating cell dependency of the enhancement. This enhancement was not dependent on the IFN species, including IFN-β, IFN-α (leukocyte), and IFN-α (lymphoblastoid), although the cells were variably sensitive to these IFN species. In contrast, the enhanced antiproliferation was critically dependent on the species of antineoplastic agents, and was selective to VCR and adriamycin among those tested under the present experimental conditions. The sequential exposure of H.Ep #2 cells to IFN and VCR induced the enhancement but exposure to VCR followed by IFN did not, suggesting that IFN-induced cell modification made the cells more sensitive to VCR. Either IFN or VCR was successfully replaced by colchicine, an antimicrotubule agent, but not by cytochalasin D, an antimicrofilament agent, suggesting the involvement of microtubule modification in the enhanced antiproliferation observed with IFN and VCR.

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Spontaneous metastasis of highly metastatic variants, B16 melanoma BL-6 and colon adenocarcinoma 26 NL-22, was examined. Tumor cells were inoculated into the right front footpad and the original tumors were removed by amputation of the forelimb at an appropriate time after tumor inoculation. Spontaneous lymph node and lung metastases occurred with B16 BL-6 and spontaneous lung metastasis occurred with NL-22. Analysis of the time-dependent formation of lymph node and lung metastases of BL-6 indicated that lung metastasis could be formed after the lymph node metastasis. Metastasis is influenced by the mouse strain, and both inbred and F₁ hybrid mice of syngeneic origin could be used as host animals. By using these metastatic variants, two spontaneous metastasis systems were established. In order to evaluate the systems, the effects of 5-fluorouracil (5-FU) and adriamycin (ADM) were examined. 5-FU was effective against the metastases of both tumors, and ADM was moderately effective against B16 BL-6 metastasis.

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