The activity of aryl hydrocarbon hydroxylase (AHH) in the lung from C3H/He and DBA/2 strains of mice was apparently increased by the oral administration of benzo [a] pyrene, but the enzyme activity in the liver was not. Properties of AHH enzymes in the lung microsomes from mice treated intraperitoneally with 3-methylcholanthrene (induced enzymes) were compared with those treated with corn oil (constitutive enzymes). The two enzymes were similar in pH-activity curve and the apparent K_m for NADPH or NADH, but differed in the apparent K_m for benzo [a] pyrene; the value for the induced enzyme (6μM) being lower than that for the constitutive enzyme (25μM). Both 5, 6- and 7, 8-benzoflavones and 2, 2'-bipyridine inhibited the activity of the two enzymes similarly, but N-benzyl-N, α-dimethylphenethylamine hydrochloride and 2-diethylaminoethyl diphenylpropylacetate inhibited the activity of the constitutive enzyme more severely than that of the induced enzyme. Cyclohexene oxide, 1, 1, 1-trichloropropane oxide, and leupeptin inhibited the activity of the constitutive enzyme slightly, but enhanced the activity of the induced enzyme. The significance of these differences was discussed briefly in relation to the carcinogenicity of polycyclic hydrocarbons.

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Effect of urokinase on the tumor growth and metastasis formation of rabbit V2 carcinoma, having low thromboplastic and high fibrinolytic activities, was examined. Weight of the tumor and lymphogenous metastases tended to increase, but the number of metastatic foci in the lungs was unchanged by the administration of urokinase. Diminution of fibrin deposits and connective tissue reaction in association with increase in the pattern of invasive growth was recognized at the advancing border of the tumors in the urokinase-treated group. In the intravenously induced pulmonary metastases, the number of metastatic foci decreased significantly in the urokinase-treated group. Fibrin was demonstrated at the site of tumor cell embolism by the conjugated anti-rabbit fibrinogen antibody. The growth of metastatic foci in the lungs was not affected by the treatment with urokinase. Enhancing effect of urokinase on fibrin resolution might promote the local tumor growth and release of tumor cells into the vessels, but interfere with the lodgement of tumor cells in remote organs.

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Antitumor activities of the cell-wall skeleton of Nocardia rubra and related bacterial fractions in autochthonous tumor-host system were tested on autografts of spontaneous mammary adenocarcinoma in SHN mice and of 3-methyl-cholanthrene-induced fibrosarcoma in ICR/JCL mice. The oil-attached cell-wall skeleton of N. rubra was the most effective in suppressing the autografts of the mammary adenocarcinoma but less of the fibrosarcoma, when the autografts were mixed with oil-attached preparation and implanted subcutaneously in the original host, while peptidoglycolipid of Mycobacterium tuberculosis Aoyama B was the most suppressive on the autografts of the fibrosarcoma but not on the mammary tumor autografts. The cell-wall skeleton of Mycobacterium bovis BCG slightly suppressed the autografts of the fibrosarcoma. Presensitization of tumor-bearing mice with the cell-wall skeleton of N. rubra resulted in a more marked, uppression on autografts of both tumors than without the presensitization, but local destruction of these tumor autografts did not induce recognizable systemic immunity to the respective tumors. Intralesional injection of cell-wall skeleton of N. rubra showed prolongation of survival days of mice with fibrosarcoma.

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Development and growth of pregnancy-dependent and -independent (autonomous) mammary tumors in inbred strain of GR/A mice and the interrelation between these different types of tumor were studied between the 67th and 78th generations. Mice were mated at 60∼70 days of age and were subjected to concurrent pregnancy until the 3rd pregnancy. Mammary tumor incidence at the 1st and 2nd pregnancies increased with the advance of generations and was 53% and 94%, respectively, at F₇₈, all of which were pregnancy-dependent in growth. Average number of tumors per mouse was 1.2 and 1.7 at the 1st and 2nd pregnancies, respectively, and average tumor age was 2.9∼3.4 months. After the 3rd parturition, 3.9% of pregnancy-dependent tumors progressed to an autonomous type. All the tumors which developed long after cessation of breeding were autonomous; the incidence was 92% and the tumor age was 9.9∼11.5 months. About 30% of tumors which appeared during the reproductive and regressed periods, all being pregnancy-dependent, recurred after retirement as autonomous tumors, corresponding to 37% of all tumors after retirement. The tumor age was earlier in recurred tumors than in new tumors. Incidence and age of mammary tumor in virgin females were 100% and 13.8 months, respectively, and these tumors were also completely autonomous. The growth rate of these autonomous tumors varied and extremely slow in all. Histologically, 74% of pregnancy-dependent mammary tumors was plaque and mammary tumor type p. On the other hand, 88% and 100% of autonomous tumors in retired and virgin females were classified as carcinoma.

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Binding of ³H-labeled dextran sulfate on transformed and untransformed cells was studied in relation to the altered growth of transformed cells by this treatment. 3T3 and SV3T3 cells, and the isolated cells (SV3T3-R5) insensitive to dextran sulfate treatment were used. The rate of binding of ³H-dextran sulfate on SV3T3 cells was dose-dependent when examined by the liquid scintillation method. It was revealed in autoradiographic analysis that there was no difference in the binding capacity of ³H-dextran sulfate among 3T3, SV3T3, and SV3T3R5 cells. The rate of binding proceeded linearly during the first 10hr and then tended to decline. Thin sections (0.3∼0.5μm) of SV3T3 cells were autoradiographed to examine the site of localization of ³H-dextran sulfate. Depending on the incubation time with the cells, ³H-dextran sulfate was located first on the cell surface and then in the cytoplasm when incubated further. Finally, silver grains were detected even in the nucleus of SV3T3 cells. This process of localization was similar in 3T3 cells. Binding of ³H-dextran sulfate on SV3T3 cells was independent of the presence of calf serum in the medium.

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7-Methylguanine is the main compound resulting from in vivo interaction between dimethylnitrosamine (DMNA) and nucleic acids, detected after strong acid hydrolysis. However, enzymic and alkaline hydrolysis of nucleic acids leads to quantitative liberation of methylamine. Methylamine isolated from liver nucleic acids of ¹⁵N-DMNA-treated rats has molecular weight of 31, thus demonstrating that DMNA-nitrogen is not involved in the binding.

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Potential value of the records of National Health Insurance programs for study on cancer morbidity was investigated by examination of those preserved in two towns in Japan. By using such records, population at risk and incidence of cancer can be readily and precisely determined. Deaths with load of cancer and survival rate of cancer were also determined without difficulty. In spite of a few limitations involved in the use of records, they are considered to be highly valuable for study on cancer morbidity and survival, mainly due to absence of under-reporting and to the feasibility of obtaining medical and other informations pertaining to cancer patients throughout the specific period.

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By the use of the indirect migration inhibition technique, blocking or inhibitory effect of autologous plasma on the production of migration inhibitory factor (MIF) from lymphocytes contacted with autologous tumor extract was studied in 45 patients with malignant tumor. When autologous plasma was added to the lymphocyte culture incubated with autologous tumor extract in 44 of these patients, inhibition of migration was completely abrogated in 9 of these patients whose lymphocytes produced MIF when cultured in plasma-free medium. MIF activity was not abolished when autologous plasma was added to the supernatant of lymphocyte culture incubated with autologous tumor extract. Inhibition of migration was not affected by the addition of allogeneic plasma from a normal subject to the lymphocyte culture. In 15 patients, MIF was not produced when lymphocytes were cultured with autologous plasma alone. These results appeared to indicate that autologous plasma of patients with malignant tumor might block or inhibit the production of MIF from lymphocytes contacted with autologous tumor extract.

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Synthetic and natural DNAs were reacted with 4-hydroxyaminoquinoline 1-oxide (4-HAQO) in an in vitro enzyme system. The amount of 4-HAQO bound to DNA varied significantly depending on the DNA used. The base sequence as well as the base composition affected the binding.
Optical melting profiles of 4-HAQO-modified DNAs were examined. Decrease in the melting temperature and broadening of the transition width were commonly observed. Melting fine structure of γ-phage DNA became less clear according to the modification. The shape of the melting curves of synthetic polynucleotides was little affected by binding, which suggests that the binding sites are distributed randomly along a DNA molecule.
Binding of 4-HAQO to a purine base may distort the secondary structure of neighboring base pairs in a DNA molecule. Degree of the distortion can be estimated as a free energy increment associated with the binding. It was found that the free energy increment differs considerably among the polynucleotides with different base sequences.

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An enzyme-immunoassay for the quantitation of human α-fetoprotein was developed employing the so-called sandwich method using filter paper discs as a solid-phase. Filter paper discs were activated with cyanogen bromide and the specific antibody to α-fetoprotein was covalently bound to the discs. The enzyme-labeled antibody was prepared by coupling the antibody to alkaline phosphatase with the aid of glutaraldehyde. The antibody-coated filter paper discs were incubated with the samples containing α-fetoprotein, which was bound to the discs, then the discs were incubated with the enzyme-labeled antibody solution. The enzyme activity bound on the discs was then measured, and was found to be proportional to the amount of α-fetoprotein in the sample.
The present method provided an accurate measurement for human α-fetoprotein in test serum in a range of 40∼1, 000ng/ml. The sensitivity was almost comparable to that of radioimmunoassay.
α-Fetoprotein levels in the normal and patient sera tested with this method were in good agreement with the values obtained by the radioimmunoassay technique.

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The organotropic effect of N-bis (2-hydroxypropyl) nitrosamine (DHPN) orally administered to mice was studied. The main targets for the carcinogenic effect of DHPN were the lung and liver, with tumors induced by doses greater than 100ppm DHPN for 16 weeks. The highest incidence was seen in liver vascular tumors including hemangioma, hemangioendothelioma, and hemangioendothelial sarcoma in mice treated with 1, 000ppm DHPN. Lung tumors were alveolar adenoma and adenocarcinoma. No pancreatic tumors were found.
The present results suggest that the carcinogenic response in mice to DHPN was similar to that in rats and guinea pigs but different from that in hamsters.

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Cryopreserved primary cultures of Syrian golden hamster embryo cells were used as the source of target and feeder cells for in vitro bioassay of carcinogenesis. Since cultures that gave the best overall response in a preliminary test were used for the bioassay, in almost every case a range of responses was obtained.
By the use of this bioassay system, the capacities of tobacco tar and its subfractions to induce morphological transformation were examined. Some fractions induced typical morphologically transformed colonies. A close correlation was observed between morphological transformation and bacterial mutagenesis.

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Morphological observations on induction of in vitro transformation were made in X-irradiated mouse embryonic 10T-1/2 cell line. Morphology of the cells growing in interior of the developing colony was almost uniform, whereas giant, morphologically altered, and transformed cells appeared in the contact area between two and three neighboring colonies. All of 10 transformed foci appeared in the contact area between 2 and 3 neighboring colonies. This suggests that the contact of colonies was an important process for the expression of radiationinduced transformation.

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Approximately 800 amino acid derivatives have been synthesized and screened in order to evaluate their antitumor activity against various transplantable rat ascites hepatomas. Among them, N⁸, N⁹-bis(butyloxycarbonylaminomethyl)-L-citrulline (A-924) was found to be highly effective against various rat ascites hepatomas. A-924, when given orally, exhibited prolongation of survival of rats implanted intravenously with ascites hepatoma cells such as AH-44, AH-66, AH-130, AH-66F, or AH-41C.

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A melanoma cell line (PL-14), established from ascites of a patient with malignant melanoma, has continued to produce melanin for 4.5 years after the initial cultivation. The cultured cells have granules which were stained black with Masson-Fontana stain, and positive to the dihydroxyphenylalanine (DOPA) reaction. Melanosomes and premelanosomes were detected in most of the cells by electron microscopy. Doubling time of the cell line was 72hr and the mode of chromosome number was 48, ranging from 40 to 86. Inoculation of the cultured cells into the hamster cheek pouch produced pigment-producing tumors.

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Formation of a free radical from carcinogenic and noncarcinogenic benz[c]acridine derivatives in the presence of proteins was examined. When aqueous mixture of benz[c]acridine and protein was stirred for a long period, shielded from light, benz[c]acridines were converted into free radicals. Albumin had the greatest effect in accelerating the free radical formation, and the effect was smaller in globulin, histone, and deoxyribonuclease. The g-value of the free radicals thus obtained was 2.005. Intensity of the electron spin resonance (ESR) signals of the free radical from carcinogenic derivatives was higher than those of the free radical from noncarcinogenic derivatives. There was a corresponding correlation among the ESR signal intensity of the free radical formed from the mixed system of benz[c]acridine and protein, charge of the K-region or ring nitrogen of the compound, and carcinogenicity of benz[c]acridines.

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A leukemic T-cell line, designated as TALL-1, has been established in continuous culture from the bone marrow of a patient with a leukemic phase of T-cell lymphosarcoma. TALL-1 cells have T-cell properties and lack Epstein-Barr virus or its genome. The cells of TALL-1 line are considered to have originated from the donor's leukemic cells on the basis of their cytogenetic, morphological, and surface features.

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Antibodies to herpesvirus type 1 and type 2 were examined in 69 Japanese females with cancer of uterine cervix, which included cases of cervical dysplasia (7 cases), carcinoma in situ (9 cases), and invasive carcinoma (53 cases), and 112 matched controls. The presence of antibodies to type 2 virus was 42% in cervical dysplasia, 11% in carcinoma in situ, and 28% in invasive carcinoma, while such was 15% in matched controls. Mean antibody titer in log₁₀ was 2.12 to type 1 and 1.65 to type 2 in women with invasive carcinoma, and 2.14 to type 1 and 1.67 to type 2 in the matched controls. The findings presented here did not support an association of type 2 virus infection with the occurrence of cervical cancer.

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Effect of clinically available chemotherapeutic agents on transplantable and tissue culture bladder carcinoma cell line, BC-47, which were syngeneic to host animals, was confirmed. Adriamycin, vincristine, and bleomycin possessed predominant antitumor activity. 1, 3-Bis(2-chloroethyl)-1-nitrosourea (BCNU) also reduced the tumor load of the host after which the tumor began to grow at the site of inoculation. Alkylating agents such as nitrogen mustard N-oxide (Nitromin), cyclophosphamide, 3, 3'-dimesyloxydipropylamine tosylate (864T), and mitomycin-C possessed a weak activity, while antimetabolites such as 5-fluorouracil, 1-(1'-furyl)-5-fluorouracil (FT-207), cytosine arabinoside, and behenoylcytosine arabinoside possessed no activity.

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Isozyme pattern of pyruvate kinase in the liver of nude mice bearing Ehrlich ascites tumor changed markedly during tumor growth. The change in isozyme pattern of pyruvate kinase was not due to infiltration or metastasis of tumor cells in the liver. Such a change in isozyme pattern of pyruvate kinase was also found in the liver of nude mice bearing canine gastric leiomyosarcoma induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), but not in the liver of nude mice bearing MNNG-induced canine gastric adenocarcinoma or human gastric adenocarcinoma.

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Tumor tissue from lymph node metastasis of nasopharyngeal carcinoma (NPC) was successfully heterotransplanted into an athymic nude mouse and the tumor grown in the nude mouse was identical in its morphology to that from the patient by optical and electron microscopy. Tumor cells at passage 2 were dispersed in vitro by enzymic digestion and smeared. Epstein-Barr virus-determined nuclear antigen (EBNA) was demonstrated in malignant epithelial cells of the smear.

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1, 1'-Ethylene-bis(1-nitrosourea) (EBNU) posesses antitumor activity against leukemia L-1210. Chemical stability, alkylating activity, and lipophilicity of EBNU and related compounds were compared. EBNU was the most unstable among several bis-N-nitrosoureas and mono-N-nitrosoureas tested. The alkylating activity of EBNU was the same as that of 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU), but higher than those of other bis- and mono-N-nitrosoureas except 1-methyl-1-nitrosourea. Lipophilicity of EBNU was extremely low compared with 1, 3-bis(2-chloroethyl)-1-nitrosourea (BCNU) and CCNU.

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Effect by chemical inducers of drug-metabolizing enzymes was compared for the production of hyperplastic nodules in hepatectomized rat liver after treatment with N-2-fluorenylacetamide (2-FAA). Results showed that PCB enhanced the development of hyperplastic nodules in hepatectomized rat liver after treatment with 2-FAA

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