By making use of the structural change of the sugar chains of liver γ-glutamyl transpeptidase associated with malignant transformation, a new method has been developed to distinguish human serum γ-glutamyl transpeptidase associated with primary hepatoma from that of non-hepatoma patients. In principle, the method consists of affinity chromatography of the desialylated serum enzyme on a Phaseolus vulgaris erythroagglutinating lectin agarose column.

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The promoting effect of phenobarbital (PB) on lung tumorigenesis in mice was examined. Pregnant ddy female mice were injected ip with a single dose of 50mg/kg 1-ethyl-1-nitrosourea at the 16th day of gestation. Offspring, 160 in total, were divided into two groups: one group of animals was fed a diet containing 0.05% PB continuously and the other was kept on the basal diet. All the animals were killed at 6 months of age and the number, size and histology of pulmonary tumors were examined. There were over 10 pulmonary tumors per animal on average, measuring from 0.5 to 10.2mm in size, and the histology varied from grade I to III in atypism. A comparative study revealed no difference between PB-treated and control mice in any aspect of the tumorigenesis. It was concluded that PB does not have promoting effect on pulmonary tumorigenesis in this system.

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Quercetin was found to have similar inhibitory effects on tumor promoter-induced phenomena to those of N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide, a calmodulin antagonist. Moreover, quercetin was shown to interact directly with the Ca²⁺-calmodulin complex. These results suggest that quercetin may act as a calmodulin antagonist, and that its antagonistic effect on calmodulin may be important in its anti-tumor-promoting action in vivo.

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Expression of herpes simplex virus type 2 (HSV-2) glycoproteins on the cell surface of two clones of a hamster cell line transformed by HSV-2 was examined by immunofluorescence tests with hamster antisera prepared against three size-class glycoprotein fractions obtained from hamster embryo fibroblast cells infected with HSV-2. Enhanced expression of one of the three size-class glycoprotein fractions (molecular weight, 82, 000-94, 000) was found in one clone (155-4-213) after replating of the cells, and in the other (155-4-03) after actinomycin D treatment. Enhanced expression of the antigen in clone 155-4-213 was inhibited by 2-deoxy-D-glucose, but not by puromycin or protease inhibitors, antipain and p-nitrophenyl-p'-guanidinobenzoate. On the other hand, the antigen expression induced by actinomycin D in clone 155-4-03 was inhibited by these four drugs. These results indicate that the expressions of the antigen in the two clones are enhanced by different mechanisms.

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The genomic DNAs of two strains of avian erythroblastosis virus (AEV), AEV-R and AEV-H, were molecularly cloned in Escherichia coli using λ Charon 16A as a vector. Comparison of the restriction maps of the cloned DNAs with that of AEV-ES4 DNA revealed that R strain is identical with ES4 strain, but totally differs from H strain. The erbB gene product of AEV-R and that of AEV-H were shown to be glycoproteins with molecular weights of 68, 000 and 72, 000, respectively. Nucleotide sequence analysis of the 3' part of the erbB gene showed that the erbB gene in AEV-R is 126 base pairs (bp) shorter than that in AEV-H, which might result in some difference in tumorigenicity between these viruses.

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A mammary tumor-associated antigen (MTAA) of the murine mammary tumor virus (MuMTV)-induced spontaneous mammary tumors of C3H/J mice was purified and partially characterized. The crude extract of the mammary tumor, when subjected to DEAE-cellulose chromatography and eluted with a discontinuous NaCl gradient, provided three major protein peaks, of which only the first (F₁) possessed the MTAA activity. The antigen was further purified by subjecting F₁ to polyacrylamide gel electrophoresis. The MTAA was a glycoprotein with a molecular weight of approximately 83, 000. The antigen was localized in the plasma membrane and was different from the MuMTV structural antigens. Circulating antibodies against the MTAA were observed in the sera of tumor-bearing mice but not in that of tumor-free mice.

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Immunological relatedness of a non-virion, murine mammary tumor-associated antigen (MTAA) and human breast cancer was demonstrated in this study. The MTAA was isolated from spontaneous mammary tumors (MMT) of C3H/J mice. An anti-serum specific for the MTAA was prepared by exhaustively absorbing the rabbit anti-serum to the MMT extract with tissue pellets of the pooled organs of tumor-free female mice. The observed cross-reaction of human malignant breast tumor (MBT) tissues with the absorbed antiserum further absorbed with normal human breast tissues suggested the presence of the MTAA or a related antigen in the MBT. No MTAA reactivity was found in human benign breast tumor. Circulating antibodies against the MTAA were recorded in all of 14 preoperative patients with MBT. Up to 18 months following surgical removal of the MBT, antibodies could be detected in the sera, though the reactivity was significantly lower than that of th sera of preoperative patients, and eventually disappeared. The antibodies were absent in patients with benign breast tumor and other neoplastic diseases, except in one patient with cancer of the cervix, and in healthy women.

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DNA lesions induced by active oxygen species generated from N-hydroxy-2-naphthylarnine were detected by an alkaline elution technique using cultured normal human lung fibroblast cells. The lesions were detected dose-dependently when cells were treated with the carcinogen either at 0° or at 20°. Their formation was strongly dependent on pH and increased with alkalinity up to pH 8.2 in parallel with the formation of hydrogen peroxide. Inhibition was observed by catalase, superoxide dismutase, and benzoic acid which is a typical hydroxyl radical scavenger. Other hydroxyl radical scavengers, mannitol and ethanol, were only effective when a cell-free in vitro reaction system was used, followed by alkaline elution. These results imply first that hydrogen peroxide and superoxide anion radicals generated during the conversion of N-hydroxy-2-naphthylamine to nitroxide radical are involved in the formation of DNA lesions and second that hydroxyl radical produced by an intracellular metal ion-catalyzed reaction might finally react with DNA bases and the DNA backbone.

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Large increases of granulocytes and monocytes were found in the blood of mice bearing fibrosarcoma. Extraction of the tumor tissue with isotonic saline yielded a colony-stimulating factor (CSF). Further extraction of the saline-insoluble materials with 0.1% sodium dodecyl sulfate afforded another pool of CSF. Incubation of the tumor cells in vitro resulted in the accumulation of CSF activity in the culture medium. The CSF from these sources produced both granulocyte colonies and macrophage colonies in murine bone marrow cell culture. Subsequently, the activity producing granulocyte colonies was separated from that producing macrophage colonies by isoelectrofocusing and repeated gel-filtration chromatography. It was also shown that anti-L cell CSF antiserum neutralized the macrophage CSF activity but not the granulocyte CSF activity. These results show that the granulocytosis-inducing tumor produces two types of CSF.

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The effect of reflux of the duodenal contents on the development of gastric stump carcinoma induced in male rats was studied. Two gastro-jejunal anastomoses were made in the resected stomach of 28 rats and about half of the rats were also given a single dose of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). Well-differentiated adenocarcinomas developed in the resected stomachs with and without MNNG administration at incidences of 40% in the former and 23% in the latter. All the carcinomas were localized in the vicinity of the gastro jejunal anastomosis, at which the proximal jejunal segment was drained. Several mucosal changes were found predominantly in the fundic mucosa surrounding the anastomosis, i.e., ulcer, foveolar hyperplasia, intestinal metaplasia and atypical hyperplasia. On the other hand, there was little mucosal change surrounding the gastro jejunal anastomosis of the distal jejunal segment. These findings suggest a direct correlation between the exposure of mucosa of the anastomotic region to the duodenal contents and the development of adenocarcinoma.

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The early cellular responses to antitumor immunomodulators and conventional inducers, especially the polymorphonuclear leukocyte (PMN) responses, were examined in the peritoneal cavity of mice to investigate their effect on primary defense mechanisms. Immunomodulators were classified into 5 groups in terms of PMN response on the basis of its duration (declining or persistent) and extent (high or low induction): 1) TAK (β-1, 3-glucan)-type (high, persistent), 2) lentinan-type (high, declining), 3) yeast mannan-type (low, declining), 4) LPS (lipopolysaccharide)-type (low, persistent), 5) others (no effect). Since the general PMN response is of the declining type, the persistence of PMN with TAK-and LPS-type immunomodulators is a characteristic of the PMN-inducing activity. With respect to the extent, TAK- and lentinan-type immunomodulators induced larger numbers of PMN and macrophages than conventional inducers. These results suggest that some types of immunomodulators have effects on the early host-defense mechanism. From the viewpoint of the general self-defense mechanism we also compared these PMN responses with those to bacteria and to tumor inoculation, and the properties of substances inducing high PMN response, i.e., those with the quality of “foreignness, ” are discussed.

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Iodinated human interferon αA (HuIFN-αA) was found to bind specifically to IFN-sensitive RSa cells: the dissociation constant was 8.7×10^-10M and the estimated number of receptor sites per cell was 1110. Seven cell lines that were either insensitive or of low sensitivity to the antiproliferative effect of IFN were found to contain a much smaller (3-to 4-fold) number of receptor sites, but the dissociation constants of these binding sites were of the same order of magnitude as those of receptors on RSa cells. Under the present experimental conditions, cell resistance to the antiproliferative effect of IFN is closely associated with the number of receptor sites.

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