Turcot's syndrome (TS) Is a rare disorder associated with the development of both brain and colon neoplasms. Because of the very low incidence of the disease, its molecular basis remains unclear. Presented is a TS case of a 30‐year‐old Japanese male with a histopathologically confirmed diagnosis of both brain tumor (glioblastoma multiforme) and colon tumor (well‐differentiated adenocar‐clnoma). Germline mutations of the p53 gene, somatic mutations of the Ki‐ras, p53and APC genes, and microsatel‐lite Instability (MSI) was examined using polymerase chain reaction (PCR)‐slngle strand conformation polymorphism analysis, followed by PCR‐dlrect sequencing, and sequencing after subclonlng. No germline mutations of the p53 gene were found. Somatic mutations of Kl‐ras and APC genes were found in the colon adenocarcinoma but not in the brain tumor. No somatic mutation of the pS3 gene was present in either colon or brain tumors. Microsatellite Instability of both colon and brain tumors was positive in two of four loci. These results indicate that the colon tumor of the TS patient carries the Kl‐ras and APC gene mutations. The finding of MSI in both the brain and the colon tumors may support the hypothesis that alterations of DNA repair genes are involved in the tumor development of the TS patient.

Regressive effects of four chemopreventive agents [5‐hydroxy‐4‐(2‐phenyl‐(E)‐ethenyl)‐2(5Hfura‐none (KYN‐54), S‐methyl metbanethiosulfonate (MMTS), chlorogenic acid (CA), and piroxicam] on azoxymethane (AOM)‐induced aberrant crypt foci (ACF) in the colon of male F344 rats were examined by dietary exposure. At six weeks of age, 60 rats of groups 1 through 5 received subcutaneous injections of AOM (15 mg/kg body weight) once a week for three weeks. Twelve weeks after the first carcinogen injection, wben the occurrence of ACF was maximal, the rats in groups 2 through 5 were started on diet containing the test chemicals as follows: group 2, KYN‐54 (0.02%); group 3, MMTS (0.01%); group 4, CA (0.025%); and group 5, piroxicam (0.0125%). Group 1 (20 rats) was kept on the basal diet alone, and group 6 (12 rate) served as an untreated control. Rats in each group were killed at 6, 12, 18, or 24 weeks after the start of the experiment, and the yield of ACF in the colon of each group at 18 or 24 weeks was compared with that at 12 weeks. The number of ACF per rat colon of each group at 18 or 24 weeks was smaller than that at 12 weeks. The reduction rates at 18 weeks were 7% in group 1 (AOM alone), 11% in group 2 (AOM+KYN‐54), 10% in group 3 (AOM+MMTS), 51% in group 4 (AOM + CA) (P 0.01), and 33% in group 5 (AOM+piroxicam) (P<0.02), while at 24 weeks they were 12%, 26%, 51% (P<0.002), 43% (P <0.05), and 70% (P <0.001), respectively. These results indicate that chemopreventive agents for large bowel carcinogenesis, i.e., KYN‐54, MMTS, CA, and piroxicam, are not only able to prevent the development of ACF, but also can regress ACF, which are regarded as precursor lesions of colorectal cancer.

As part of the safety assessment of madder root (MR), a food colorant extracted from madder (Rubia tinctorum), toxicity tests were undertaken using (C57BL/6 x C3H)F1 mice of both sexes. An acute toxicity test was performed by 14-day administration of MR dissolved in distilled water by gavage at doses of 0, 500, 2000, 3500, and 5000 mg/kg body weight to groups of each sex. One male mouse dosed at 5000 mg/kg body weight was dead before the end of the study, indicating that the maximum tolerated dose of MR was between 3500 and 5000 mg/kg body weight. A subacute toxicity test of MR was performed using 62 mice of each sex, mixing their diets with MR at concentrations of 0, 0.3, 0.6, 1.25, 2.5, and 5% for 90 days. All mice tolerated these doses of MR well. The body weight gains of either sex were not affected by the treatment. None of the mice treated with MR showed clinical signs of toxicity. Histopathological examinations showed retention cysts of the kidneys and epidermal vaginal cysts in a few of the treated or control mice. No hyperplastic, preneoplastic, and neoplastic lesions and no pathological findings of toxicity were found. These results suggest that dietary exposure of MR at these doses has no acute or subacute toxic effects on mice.

The chemopreventive effects of two xanthophylls, astaxanthin (AX) and canthaxanthin (CX), on urinary bladder carcinogenesis induced by N-butyl-N(4-hydroxybutyl)nitrosamine (OH-BBN) was investigated in male ICR mice. Mice were given 250 p.p.m. OH-BBN in drinking water for 20 weeks and after a 1 week interval with tap water, water containing AX or CX at a concentration of 50 p.p.m. was administered during subsequent 20 weeks. Other groups of mice were treated with AX or CX alone or untreated. At the end of the study (week 41), the incidences of preneoplastic lesions and neoplasms in the bladder of mice treated with OH-BBN and AX or CX were smaller than those of mice given OH-BBN. In particular, AX administration after OH-BBN exposure significantly reduced the incidence of bladder cancer (transitional cell carcinoma) (P < 0.003). However, the inhibition of the frequencies of such lesions in mice treated with OH-BBN and CX was not significant. Treatment with AX or CX also decreased the number/nucleus of silver-stained nucleolar organizer region proteins (AgNORs), a new index of cell proliferation, in the transitional epithelium exposed to OH-BBN. Preneoplasms and neoplasms induced by OH-BBN, and the antiproliferative potential, was greater for AX than CX. These results indicate that AX is a possible chemopreventive agent for bladder carcinogenesis and such an effect of AX may be partly due to suppression of cell proliferation.

The relationship between the numerical aberrations of chromosome 7 in interphase cells and the clinicopathological behavior of breast tumors was investigated in 51 touch imprinted preparations of breast tumors. Using fluorescence in situ hybridization with a chromosome 7-specific DNA probe, the fluorescein-isothiocyanate (FITC) spots mean and the representative copy number of each breast tumor were examined. The FITC spots mean (2.34) of 40 breast cancers increased compared with that of 11 benign lesions (1.98) (P < 0.02). The FITC spots mean tended to increase with the advancing stage and tumor size of the breast cancer. The FITC spots mean in the case with metastasis was also of a higher value than that without metastasis (P < 0.01). Furthermore, the existence of trisomy or over-trisomy of the copy number was related to the advancing stage and tumor size (P < 0.05 and P < 0.01, respectively). These findings suggest that the FITC spots mean and polysomy of the number of chromosome 7 may be highly predictive for breast tumor aggressiveness.

The effect on colon and liver carcinogenicity in rats of a single X-irradiation exposure given either before or after methylazoxymethanol (MAM) acetate was studied in ACI/N rats of both sexes. A single dose of X-irradiation (3 Gy) was administered either 3 months before or after three weekly s.c. injections of MAM acetate (25 mg/kg body weight). At 365 days after the start, the incidence and multiplicity of MAM acetate-induced intestinal tumors were enhanced by X-irradiation either prior to or after the MAM acetate treatment. In addition, X-irradiation before MAM acetate increased the incidence of hepatocellular foci in either sex. In females, X-irradiation either before or after MAM acetate exposure decreased intestinal tumorigenesis. These findings suggest an apparent synergism of these agents in intestinal carcinogenesis of male rats.

The effects of X-irradiation on N-methyl-N-nitrosourea (MNU)-induced multi-organ carcinogenesis were examined in both sexes of ACI/N rats. At 6 weeks of age, rats in groups 1 (25 males, 25 females) and 3 (24 males, 23 females) received a single i.p. injection of MNU (25 mg/kg body weight), while those in groups 2 (25 males, 26 females) and 4 (25 males, 25 females) were administered the carcinogen at a dose of 50 mg/kg body weight. At 10 weeks of age, groups 3 and 4 were X-irradiated at a dose of 3 Gy. Group 5 (24 males, 24 females) received X-irradiation alone. Group 6 (21 males, 21 females) served as an untreated control. As a result, neoplasms developed mainly in the digestive tract, kidney, uterus, and hematopoietic organ in groups 1-5. The incidences of adenocarcinoma in small and large intestines of male rats of group 4 (50 mg/kg MNU and X-irradiation) (small intestine: 48%, large intestine: 32%) were significantly higher than those of group 2 (50 mg/kg MNU) (small intestine: 17%, P < 0.05; large intestine: 8%, P < 0.05), and also the frequency of adenocarcinoma in the large intestine of males of group 3 (25 mg/kg MNU and X-irradiation) (22%) was significantly greater than that of group 1 (25 mg/kg MNU) (0%, P < 0.05). These results indicated that X-irradiation enhanced the development of intestinal neoplasms induced by MNU in male ACI/N rats.

Preventive effect of magnesium hydroxide on carcinogen-induced, large bowel carcinogenesis was examined in three experiments using F344 rats. Experiment I: Rats received dietary administration of magnesium hydroxide at concentrations of 500 or 1,000 ppm after treatment with methylazoxymethanol (MAM) acetate (25 mg/kg, 3 times). These rats had a lower incidence of large bowel neoplasms than animals given MAM acetate alone. Reduction of the tumor incidence was especially significant at a dose of 500 ppm. Experiment II: Rats given magnesium hydroxide (250, 500, or 1,000 ppm) together with 1,2-dimethylhydrazine (DMH) (20 mg/kg, 10 times) showed a lower multiplicity of large bowel tumors than those given DMH alone. Experiment III: The labeling indices of the cryptal cells of the large bowel (cecum or proximal colon or distal colon) or rates given magnesium hydroxide for 4, 6, or 8 weeks after treatment with MAM acetate (25 mg/kg, 3 times) were smaller than those of animals given MAM acetate alone, indicating that magnesium hydroxide suppressed, carcinogen-induced epithelial cell (large bowel) proliferation. The results of the three experiments suggest that magnesium, one of the essential metals, is a promising chemopreventive agent in humans.

The modifying effects of indole‐3‐carbinol (I3C) and sinigrin (SIN) on the initiation and post‐initiation phases of tongue carcinogenesis induced by 4‐nitroquinoline 1‐oxide (4‐NQO) were investigated in male ACI/N rats. Rats were divided into eight groups: group 1 was given 4‐NQO (10 ppm) in the drinking watar for 12 weeks, starting at 7 weeks of age; groups 2 and 3 were given 4‐NQO and fed the diets containing I3C (1,000 ppm) and SIN (1,200 ppm) for 14 weeks, respectively, starting at 6 weeks of age; groups 4 and 5 were given 4‐NQO and then they were fed I3C and SIN containing diets for 23 weeks, respectively, starting one week after 4‐NQO exposure; groups 6 and 7 were given I3C and SIN alone, respectively, during the experiment; group 8 served as an untreated control. At the termination of the experiment (week 37), the incidence of tongue neoplasms (squamous cell papilloma and carcinoma) in group 2 (1/15,7%), group 3 (1/15, 7%), group 4 (3/15, 20%) or group 5 (2/15, 13%) was significantly smaller than that in group 1 (12/17,71%) (P= 0.0003, P=0.005 or P=0.002). No tongue carcinomas developed in rats of groups 2, 3, and 5. Similarly, the incidence of preneoplastic lesions (hyperplasia and dysplasia) of the tougue in group 2 (11/15, 73%), group 3 (10/15, 67%), group 4 (11/15, 73%) or group 5 (10/15, 67%) was significantly lower than that in group 1 (17/17, 100%) (P=0.04 or P=0.02). There were no tongue neoplasms in rats of groups 6, 7, and 8. Administration of I3C and SIN also caused significant decreases in the number and area of silver‐stained nucleolar organizer regions protein (AgNORs), a new cell proliferation index, of tongue squamous epithelium. Thus, I3C and SIN inhibited rat tongue carcinogenesis in both the initiation and post‐initiation phases, when administered in these respective phases together with, or following treatment with, 4‐NQO.

Modifying effects of a fungal product, flavoglaucin, and four plant-derived chemicals, shikonin, gingerol, oleanolic acid and paeoniflorin, on intestinal carcinogenesis were examined in a rat model using azoxymethane (AOM). A total of 280 male F344 rats, 6 weeks old, were divided into 12 groups. Group 1 (30 rats) was given two subcutaneous injections of 15 mg/kg of AOM at the start of the experiment. Groups 2 (30 rats), 3 (20 rats), 4 (20 rats), 5 (30 rats) and 6 (30 rats) received a test chemical (flavoglaucin, shikonin, gingerol, oleanolic acid or paeoniflorin, respectively) in the diet at a concentration of 0.02% for 3 weeks, during which time AOM was applied, and then kept on basal diet until the end of experiment (one year). Groups 7-11 (each 20 rats) were given a test chemical corresponding to Groups 2-6, respectively. Group 12 (20 rats) served as a control. The incidence and average number of intestinal tumors in Group 2 (47%, 0.57 +/- 0.68) were significantly less than in Group 1 (74%, 1.07 +/- 0.87) (P < 0.05, respectively). Multiplicity of intestinal neoplasms of Group 3 (0.55 +/- 0.60) or 4 (0.47 +/- 0.51) was also significantly smaller than that of Group 1 (P < 0.05 and P < 0.01, respectively). These results suggest that flavoglaucin, shikonin and gingerol might be promising chemopreventive agents for intestinal neoplasia.

Carcinogenicity of 1-nitropyrene (NP) oxides (1-NP 4, 5-oxide and 1-NP 9, 10-oxide) and related chemicals (1-NP and 1-nitro-6-hydroxypyrene) was examined in the newborn mouse model by i.p. administration at 1, 8, 15 days after birth (each chemical was given at a total dose of 700 nmol per mouse). Low incidences of hepatocellular neoplasms were recognized in male mice exposed to either of these chemicals. However, the incidences were not significantly different from those of animals given solvent alone or of non-treatment. Lymphoma was infrequently seen in female mice given some of tested chemicals. The incidences were also not significantly different from those of mice with the solvent alone or of the controls. The results suggest that although these aromatic hydrocarbons exert genotoxicity or mutagenicity, they may not be potent carcinogens, or the assay with use of newborn mice may be insufficient to monitor carcinogenicity of such chemicals.

The effect of magnesium hydroxide on the epithelial proliferation of the large bowel was examined using rats given methylazoxymethanol (MAM) acetate. Dietary administration of magnesium hydroxide at 250, 500, 1000 or 2000 ppm. for 1, 3 or 5 weeks did not influence the cell cycle of the cryptal cells of the large bowel. However, the exposure to magnesium hydroxide under these conditions lowered the bromodeoxyuridine labeling index of the cells of the large bowel of the rats which had been initiated by MAM acetate (25 mg/kg, 3 times). The decrease in labeling index was more apparent in the proximal segment than in the distal segment. Such an inhibitory effect on the DNA synthesis of the epithelial cells by magnesium hydroxide may be related to the suppressive action of the trace element on the carcinogen-induced large bowel carcinogenesis.

Modifying effects of 5-hydroxy-4-(2-phenyl-(E)ethenyl)-2(5H)-furanone, a novel synthesized retinoid (KYN-54), on intestinal carcinogenesis were examined in a rat model using azoxymethane (AOM). A total of ninety male F344 rats, 6 weeks old, were divided into 4 groups. Group 1 (20 rats) was fed a diet containing KYN-54 at a concentration of 0.02% for 3 weeks, during which time 2 s.c. injections of azoxymethane (15 mg/kg) were applied and then kept on a basal diet until the end of the experiment (1 year). Group 2 (30 rats) was given azoxymethane as in group 1 and fed the basal diet throughout, without synthetic retinoid exposure. Group 3 (20 rats) was administered KYN-54 at the commencement of the experiment, but not given the carcinogen. Group 4 (20 rats) received a basal diet alone throughout the experiment and served as a control. Intestinal tumors were seen in groups 1 and 2, their incidence and average number in group 1 (74%, 1.07 +/- 0.87) being significantly less than in group 2 (39%, 0.56 +/- 0.78) (P < 0.02 and P < 0.05, respectively). These results suggest that the synthetic retinoid might be a promising chemopreventive agent for intestinal neoplasia.

The effects of some well-known anticancer agents, adriamycin (ADR), actinomycin D (ACT), and cisplatin (CIS), on hepatocarcinogenesis induced by N-2-fluorenylacetamide (FAA) were examined in male ACI/N rats. Animals were divided into 15 groups and treated as follows: group 1, 0.02% FAA diet (13 wk); group 2, FAA diet and 0.05% phenobarbital (PB) diet (16 wk); group 3, FAA diet and ADR (3 ip injections of 1.00 mg/kg body weight/wk); group 4, FAA, ADR, and PB; group 5, FAA and ACT (3 ip injections of 0.02 mg/kg body weight/wk); group 6, FAA, ACT, and PB; group 7, FAA and CIS (3 ip injections of 1.00 mg/kg body weight/wk); group 8, FAA, CIS, and PB; group 9, ADR; group 10, ADR and PB; group 11, ACT; group 12, ACT and PB; group 13, CIS; group 14, CIS and PB; group 15, nontreatment. At the end of the experiment (30 wk), the incidence of preneoplastic and neoplastic hepatocellular lesions was evaluated. All three tested compounds, especially CIS, inhibited the development of preneoplastic and neoplastic liver lesions, indicating CIS could be valuable as a therapeutic agent for hepatocellular malignancies.

The carcinogenicity of cochineal, a red colouring used in food and other products, was studied in a 2-yr bioassay in B6C3F1 mice. Groups of 50-55 mice of each sex were given 0, 3 or 6% cochineal in the diet for 2 yr. Mice of all groups developed tumours including hepatocellular adenomas or carcinomas, pulmonary adenomas or adenocarcinomas and lymphomas or lymphatic leukaemias, and the incidences of these tumours were not significantly different in treated and control groups. The results indicate that cochineal lacks carcinogenicity in mice and are consistent with those of in vitro short-term assays of cochineal and of carminic acid, an active principle of cochineal.

We report a rare case of gastric collision tumor (carcinoid and adenocarcinoma) with gastritis cystica profunda that developed in a 49-year-old Japanese man. Early gastric cancer (moderately differentiated tubular adenocarcinoma) was present at the edge of an ulcer in the posterior wall of the upper gastric body. In addition, a carcinoid tumor was found adjacent to adenocarcinoma. This tumor displayed ribbonlike or trabecular patterns, and numerous constituent cells were positive for the argyrophil reaction with Grimelius' stain and serotonin. Electron microscopic features of this tumor confirmed typical carcinoid. There was no merged appearance between both tumors, suggesting collision-type tumor.

We present a rare case of carcinosarcoma (malignant ameloblastoma and fibrosarcoma) of the left maxilla that developed in a 63-year-old Japanese man. The tumor recurred repeatedly despite multiple surgical removals, radiotherapy, and chemotherapy and led to progressive cachexia; the patient died after 3.8 years of hospitalization. Histopathologic examination revealed that the recurrent tumor was carcinosarcoma, which had progressed from malignant ameloblastoma with fibroma. An autopsy confirmed the diagnosis of malignant mixed tumor with lung metastasis of malignant ameloblastoma and fibrosarcoma.

Primary mucoepidermoid carcinoma of the thymus developing in an 80-year-old Japanese man is described. This is the third case report of this rare tumour which was diagnosed following fine needle aspiration cytology (FNAC) of a metastatic lesion in the left humerus. FNA showed the typical cytological findings of mucoepidermoid carcinoma, that is the presence of squamous, glandular and intermediate neoplastic cells. Histology at autopsy confirmed these findings.

The modifying effects of sinigrin (Sin) and indole-3-carbinol (I3C) on the hepatocarcinogenesis induced by diethylnitrosamine (DEN) were investigated in male ACI/N rats. Rats were divided into six groups: group 1 was given DEN (40 p.p.m.) in the drinking water for 5 weeks, starting at 7 weeks of age; group 2 was treated with DEN and diet containing 1200 p.p.m. Sin; group 3 received DEN and diet containing 1000 p.p.m. I3C; group 4 was given Sin diet alone; group 5 was given I3C diet alone; and group 6 served as controls. The diet containing Sin or I3C was fed to the rats starting at 6 weeks of age until 1 week after the carcinogen exposure. At termination of the experiment (week 29), the incidences of iron-excluding altered foci (11.22 +/- 3.22/cm2) and liver cell tumors (6/12, 50%) and the tumor multiplicity (0.9/rat) in rats of group 2 were significantly smaller than those of group 1 (foci incidence, 48.33 +/- 6.34/cm2, tumor incidence, 10/10, 100%; multiplicity, 9.5/rat) (P less than 0.02). Similarly, the incidence of iron-excluding hepatocellular foci (17.65 +/- 4.67/cm2) and tumor multiplicity (2.4/rat) with a slight reduction of tumor incidence (9/12, 75%) in rats of group 3 were significantly lower than those of group 1 (P less than 0.001). There were no liver cell neoplasms in rats of groups 4, 5 and 6. Thus, Sin and I3C inhibited the hepatocarcinogenesis induced by DEN when they were administered concurrently with the carcinogen.

The effect of radiation on chemical hepatocarcinogenesis was examined in 3 groups of male ACI/N rats. In Group I, 21 rats received dietary administration of N‐2‐fluorenylacetamide (FAA) (0.02%) for 16 weeks. Six of the rats were killed at the cessation of FAA exposure. The remaining rats were then given the basal diet until termination (32 weeks). In Group II, 16 rats were given FAA for 16 weeks. The animals were then given radiation (whole body; 3 Gy) and kept on the diet for the subsequent 16 weeks. Thirteen rats of Group III were kept on the basal diet throughout the experiment. They received radiation for 16 weeks after the start of the experiment. Liver tumors were obtained in Groups I and II. The multiplicity of the neoplastic nodules or hepatocellular carcinomas of Group II (6.5 ± 2.5 or 1.4 ± 0.9) was significantly greater than that of Group I (2.9 ± 1.7 or 0.3 ± 0.4, respectively) ( P < 0.001). Furthermore, the incidence of hepatocellular carcinoma of Group II (13/16) was also significantly higher than that of Group I (4/15) ( P < 0.003). The results clearly indicate a synergistic effect of radiation with FAA on the hepatocarcinogenesis. The effect of radiation in this rat model appeared to be on the early progression of the carcinogenesis.