Metastasis formation of transplantable ascites hepatoma (AH-130) and Yoshida sarcoma was markedly enhanced by the administration of parathyroid hormone in the initial stage of transplantation. Judging from the fact that enhancement of metastasis formation could not be observed in animals receiving calcium chloride solution, it was difficult to assume that such an effect of this hormone was the result of hypercalcemia caused by this hormone.

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Atrophic change was observed in reticulum cells in the lymph node of rats following the administration of parathyroid hormone, and inhibitory effect of this hormone on the production of antibody was recognized.

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Benzo[a]pyrene and 4-nitroquinoline 1-oxide in diluted ethanol were administered to mice by esophageal infusion or by forced drinking in order to see whether such administration induces esophageal and other alimentary cancer. In addition to many papillomas, two carcinomas of the esophagus were produced, one in each of the groups which had forced drinking of 4-nitroquinoline 1-oxide or benzo-[a]pyrene. Many papillomas and cancers of the forestomach were found among mice subjected to the infusion of 4-nitroquinoline 1-oxide or to forced drinking of 4-nitroquinoline 1-oxide or benzo[a]pyrene, but no gastric adenocarcinoma was produced in any groups of mice. Carcinomas of the pharynx, tongue, lower jaw, and skin were found among mice which received carcinogens by either infusion or forced drinking. No cancer was detected among mice administered only diluted ethanol.

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Population analysis was made of a cancer clone derived from a single tumor cell, using a clonal strain of the rat ascites hepatoma, CL-1-AH-66F. The sensitivity to nitrogen mustard N-oxide and chromosomal constitution were studied, after establishing subclonal tumors from the original clone. The results indicated the following facts:
1) The cancer clone is not a uniform but a complex population of cells with different degree of sensitivity to chemicals.
2) The degree of drug sensitivity, either of the original clone or its subclones, fluctuates spontaneously within a certain range during serial animal passage.
3) No specific correlation is found between the degree of drug sensitivity and chromosomal constitution of the subclonal tumors.
4) Transient change in the modal chromosome number and ploidy shift occurred during animal passage.

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Localization and activity of β-glucuronidase in normal and abnormal tissues were examined histochemically employing Naphthol AS-OL glucuronide and pararosaniline hexazonium chloride. Liver, spleen, and kidney of normal rat showed higher β-glucuronidase activity, while corresponding tissues of normal mouse showed a rather lower activity.
Adenomatous nodule (benign hepatoma) developing in the liver of mice chronically poisoned by carbon tetrachloride showed higher activity than other portions of the same liver. β-Glucuronidase activity of Yoshida solid sarcoma was not higher than that of host rat liver, and this enzyme was localized in the juxtanuclear region of ascites cells, corresponding in location to "azur rosette".

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A transplantable mouse tumor, the fructose sarcoma, was transplanted in mice and conditioned rats, and their susceptibilities to viral infection were compared. Col-Sk and Mengo encephalitis viruses multiplied better in rat-grown tumors than in mouse-grown tumors and, at the same time, exhibited marked cytophathogenic effect on rat-grown tumors. Effect of viral infection upon rat-grown tumors is not influenced by the age of hosts.
On the other hand, propagation of western and eastern equine encephalitis viruses is lower in rat-grown tumor than in mouse-grown tumor and gives almost no influence on tumor growth. Thus, in vivo susceptibility of tumor cells to viral infection differs in homologous and heterologous hosts. However, growth potentialities of tumor cells grown either in mice or conditioned rats are the same, so far as they are in the active growth phase.

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Nucleotide composition of RNAs prepared from subcellular fractions of normal rat liver, liver of rats fed 3'-methyl-4-dimethylaminoazobenzene (3'-Me-DAB), and in hepatoma induced by 3'-Me-DAB was examined. It was found that the nucleotide composition of nuclear and microsomal RNA after 4 and/or 8 weeks of azo dye-feedingd id not differ from that of RNA from the corresponding fraction of normal rat liver. No significant difference was observed in the nucleotide composition of cytoplasmic RNA among the normal, hepatoma, and non-tumorous part of hepatoma-bearing liver. However, an increase in guanylic acid content was observed in the nuclear RNA of hepatoma induced by 3'-Me-DAB, showing an access to the type of cytoplasmic RNA.
Significance of the increase in guanylic acid content in nulcear RNA in hepatoma induced by 3'-Me-DAB is discussed.

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Q_O2 and spontaneous CO₂-Uptake activity of human bladder tumor tissue were determined. Q_O2 of tumor tissue was rather independent of pathological malignancy of the tumor. Spontaneous CO₂-uptake of tumor tissue slice, which was measured after the addition of KH₂PO₄ solution into the incubation medium, in which inorganic phosphate fraction of normal Krebs-Ringer bicarbonate buffer (pH 7.4) was excluded, corresponded to the grade of malignancy.
From the value of spontaneous CO₂-uptake activity, it was assumed that a cancerous metabolic pattern could be found in non-cancerous part of the mucosal membrane of the urinary bladder with malignant tumor.

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Enzymatic conversion of a potent carcinogen, 4-nitroquinoline 1-oxide, to 4-hydroxyaminoquinoline 1-oxide and 4-aminoquinoline 1-oxide was proved with rat liver homogenate. The enzyme activities to form aminoquinoline 1-oxide were almost equally distributed in fractions of mitochondria and microsomes. Hydrogen donors, such as β-hydroxybutyrate, ethanol, or isocitrate, and corresponding reductases were required with hydrogen carriers, either NAD or NADP. Enzymatic reaction proceeded linearly for 5 hours under anaerobic condition. p-Chloromercuribenzoate and molecular oxygen inhibited the reaction. Enzymatic reduction of 4-nitroquinoline 1-oxide to 4-aminoquinoline 1-oxide was found also with homogenates of lung, skin, and kidney.
Significance of this enzymatic reduction of 4-nitroquinoline 1-oxide in the carcinogenic mechanism was discussed.

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The effects of rapidly growing tumors on the primary and secondary immune responses were studied by using Ehrlich ascites tumor in mice and Brown-Pearce carcinoma in rabbits, as assessed by bacterial α-amylase (BA)-anti-BA system.
The tumor-bearing animals responded in the same levels of anti-BA titers as control animals in primary immune response. In secondary response, in some experiments, sera of mice with ascites tumor had lower anti-BA titers than that of control animals, but it was found that ascites of mice with Ehrlich tumor contained a large amount of anti-BA antibody. Consequently, total anti-BA titers of tumorbearing mice, in secondary response also, were of the same levels or rather higher levels than that of mice.
No suppression of anti-BA response of tumor-bearing animals was observed in spite of a "nitrogen trap" of tumor, by which tumor protein was synthesized rapildy from amino acid pool of carcass.

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Pulmonary and uterine cancers, and leukemia, besides sarcomas at the site of injection, were induced in mice receiving repeated injection of 4-nitroquinoline 1-oxide in a mixture of olive oil and lecithin. In 16 effective number of mice which survived more than 6 months, 4 subcutaneous sarcomas, 7 lung cancers, 4 uterine cancers, and 11 cases of leukemia were induced. Thus, target of the carcinogen increased from that of the previous experiment, in which sarcomas and pulmonary cancers were induced by the carcinogen when the solvent mixture contained cholesterol instead of lecithin. It is worthy of note that the component of a solvent mixture for the carcinogen would change the target or is closely related to the potential activity of the carcinogen against tissues and organs in animals.

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A reticulum cell sarcoma was serially transplanted in C₃Hf mice for eight generations. Of 41 mice transplanted intraperitoneally, 34(83%) developed tumors and were autopsied after a latency of 16 to 117 days. Gross and microscopic pathology of the tumor-bearing mice is described.

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