Koji Yoshiga

Polymorphisms of the CYP1A1 and GSTM1 gene involved in oral squamous cell carcinoma in association with a cigarette dose.

The genetic polymorphisms of CYP1A1 and GSTM1 genes among 100 Japanese patients with oral squamous cell carcinomas (SCC) were investigated to evaluate the role of genetic susceptibility in carcinogenesis of the oral cavity. The presence of the rare homozygote of CYP1A1, m2/m2, was significantly more frequent in the patient group (15.0%) than the control group (8.0%) (Odds ratio (ORs) = 3.6 95% Confidential Interval (CI): 1.4-9.5). The heterozygotic variant, m1/m2, was also frequently seen in oral SCC patients. This meant that the m2 allele was observed in more than half of the patients. The null genotype of GSTM1 was found in 43.0% of the patient group. This was not significantly different from the controls (40.0%). When the life time cigarette consumption dose of the patients was considered with respect to genotypes of CYP1A1, the mean smoking index (SI) of oral SCC patients with m2/m2 was found to be less than half of the mean SI among the patients with m1/m1 genotype (P < 0.02). The ORs of the m2/m2 genotype was found to be significantly high in a comparison of various subsites of the oral cavity, except for the floor of the mouth. Our results indicate that the rare homozygote of CYP1A1, m2/m2, is associated with increased risk of oral SCC, in particular, at low cigarette dose levels. The results also suggested that the involvement of such susceptibility in oral carcinogenesis might be different between the subsites of the oral cavity.

Human mismatch repair gene, MLH1, is transcriptionally repressed by the hypoxia-inducible transcription factors, DEC1 and DEC2

Tumor hypoxia has been reported to cause a functional loss in DNA mismatch repair (MMR) system as a result of downregulation of MMR genes, although the precise molecular mechanisms remain unclear. In this study, we focused on the downregulation of a key MMR gene, MLH1, and demonstrated that hypoxia-inducible transcription repressors, differentiated embryo chondrocytes (DEC1 and 2), participated in its transcriptional regulation via their bindings to E-box-like motif(s) in MLH1 promoter region. In all cancer cell lines examined, hypoxia increased expression of DEC1 and 2, known as hypoxia-inducible genes, but decreased MLH1 expression in an exposure time-dependent manner at both the mRNA and protein levels. Co-transfection reporter assay revealed that DEC1 and, to greater extent, DEC2 as well as hypoxia-repressed MLH1 promoter activity. We further found that the action was remarkably inhibited by trichostatin A, and identified a possible DEC-response element in the MLH1 promoter. In vitro electrophoretic gel mobility shift and chromatin immunoprecipitation assays demonstrated that DEC1 or 2 directly bounds to the suggested element, and transient transfection assay revealed that overexpression of DEC2 repressed endogenous MLH1 expression in the cells. Hypoxia-induced DEC may impair MMR function through repression of MLH1 expression, possibly via the histone deacethylase-mediated mechanism in cancer cells.

Down-regulated expression of CD44 variant 6 in oral squamous cell carcinomas and its relationship to regional lymph node metastasis

The expression of the adhesion molecule CD44 variant 6 (CD44v6) was studied immunohistochemically on 38 oral squamous cell carcinomas (SCCs) and 10 biopsies of healthy oral mucosa. The relationship between the expression of CD44v6 and regional lymph node metastasis was also investigated. The expression of CD44v6 was apparently down-regulated in oral SCC, but not in normal oral mucosa. Carcinomas expressing lower levels of CD44v6 exhibited more frequent regional lymph node metastasis. The expression of CD44v6 showed no statistically significant relationship to the degree of differentiation, but tended to be down-regulated in poorly differentiated carcinoma. No significant relation was found between the expression of CD44v6 in primary and metastatic lesions.

CD44 variant 6 (CD44v6). expression as a progression marker in benign, premalignant and malignant oral epithelial tissues

The change in the expression pattern of CD44 variant 6 (CD44v6) protein in benign, premalignant, and malignant (SCC) oral epithelial lesions was studied immunohistochemically and compared with the pattern in normal mucosa in order to examine whether this gene can serve as a progression marker in patients with SCC. The principal findings is that CD44v6 expression was clearly downregulated in most cases of severe premalignant lesions as well as in most of the SCCs. The staining pattern and intensity varied according to the degree of dysplasia and to the degree of differentiation of the SCCs. Premalignant severe epithelial dysplasia cases with early features of invasion, not yet developed into SCC, showed distinctly downregulated expression of CD44v6 protein whereas hyperplastic and benign epithelial lesions (papilloma) expressed positive staining patterns comparable to those of the normal counterparts. The authors conclude that alteration in CD44v6 may occur as an early event in primary oral SCC development, as well as in premalignant severe epithelial dysplasia. It can thus, be used as a molecular progression marker when screening for oral cancer.

Total upper lip reconstruction using a free radial forearm flap incorporating the brachioradialis muscle: Report of a case

One-stage reconstruction of the upper lip using a free radial forearm flap was successfully performed with excellent functional and cosmetic results. The free radial forearm flap, including the vascularized and innervated brachioradialis muscle, has a very wide potential for reconstruction of the lip defects due to carcinoma.

Differentiation of cultured epidermal keratinocytes related to sterol metabolism and its retardation by chemical carcinogens

The amount of 5 beta-cholest-7-en-3 beta-ol of mouse dorsal skin was increased after parturition until 10 days of age, reaching a maximum 5 beta-cholest-7-en-3 beta-ol/5-cholesten-3 beta-ol ratio of 0.43. [2-14C]Acetate was incorporated almost exclusively into 5-cholesten-3 beta-ol in the basal cell culture of epidermal keratinocytes. However, when the concentration of calcium was changed from 0.07 to 1.9 mM to induce terminal differentiation of keratinocytes, a definite amount of radioactive acetate was incorporated into 5 beta-cholest-7-en-3 beta-ol. The extent of the incorporation was increased at least until 72 h after changing medium, and the ratio of radioactive 5 beta-cholest-7-en-3 beta-ol/radioactive 5-cholesten-3 beta-ol was constantly increased in this period, indicating that the accumulation of 5 beta-cholest-7-en-3 beta-ol in the cell is concomitant with the differentiation of the cell. Pretreatment with chemical carcinogens such as 7,12-dimethylbenz[a]anthracene and 20-methylcholanthrene inhibited the incorporation of radioactive acetate into 5 beta-cholest-7-en-3 beta-ol in the high calcium medium at least for the initial 24 h. After that, the incorporation was gradually restored to the normal level. Pretreatment with a tumor promoter, such as 12-O-tetradecanoyl-phorbol 13-acetate, however, did not inhibit the incorporation. Thus, sterol metabolism is suggested to be a useful indicator for differentiation of epidermal keratinocytes.

Massive Osteolysis of the Mandible With Subsequent Obstructive Sleep Apnea Syndrome: A Case Report

tation rate, white blood cell count, and C-reactive protein suggesting the existence of chronic inflammation. At the time, a tentative diagnosis of chronic osteomyelitis of the mandible was made, but this remained as an open question because there was no history of severe inflammation of the mandible. A possible diagnosis of massive osteolysis was also suspected. Because the patient had heart disease (multifocal ventricular premature beats) and no discomfort from his jaw, regular follow-up was conducted instead of surgical treatment.

Effects of intralesional injection of cisplatin dissolved in urografin and lipiodol on Ehrlich ascites tumor and normal tissues of CD-1 mice

The response of Ehrlich ascites tumor and the effect on normal tissues (kidney and small intestine) of CD-1 mice were evaluated after intralesional (i. l.) injection of cisplatin dissolved in urografin and lipiodol, which is henceforth termed CUL suspension. The results obtained were compared with the effects of i. p. and i. l. injections of cisplatin dissolved in sterile distilled water. Each of these treatment modalities involves the injection of 10 mg/kg cisplatin. The tumor response was evaluated by tumor growth-delay studies as well as by determining the percentage of cells in the S phase. Toxicity studies were accomplished by evaluation of the change in the body weight of mice and also by S-phase studies. S-phase fraction analyses were done with the use of the Cell Proliferation Kit. This commercial kit was used to measure bromodeoxyuridine (BrdU), a thymidine analogue that is incorporated into cells synthesizing DNA. Tumor, kidney, and small-intestine platinum concentrations were determined by measurement with a flameless atomic absorption spectrophotometer. The results of the tumor growth-delay studies showed that i. p. injection, with water being the drug carrier, produced the weakest antitumor effect, whereas i. l. injection of cisplatin, with lipiodol being the drug carrier, evoked the most enhanced effect. This finding was substantiated by BrdU-uptake analysis of tumor cells, wherein i. p. injections yielded the highest S-phase fraction and CUL treatment gave the lowest. Toxicity studies showed that a very significant decrease in body weight occurred in mice receiving i. p. treatment. No significant decrease in body weight was noted after i. l. treatment. BrdU analysis revealed that DNA synthesis in kidney cells and crypt cells of the small intestine was depressed after i. p. treatment. On the other hand, no significant effect was observed in the kidney or small intestine of CUL-treated mice. A correlation between the effects of the various treatment modalities (on tumors, kidney, and small intestine) and the retention of cisplatin was found.

Mandibular reconstruction with a microvascular free groin osteocutaneous graft based on the deep circumflex iliac vessels

Summary Two cases in which mandibular reconstruction was accomplished by a free groin osteocutaneous composite graft with microvascular anastomosis of its feeding deep circumflex iliac vessels are presented. The immediate and long-term postoperative results were found to be very satisfactory.

A biochemical evaluation of oral squamous cell carcinoma growth by measurement of specific activity of succinate dehydrogenase in the subrenal capsule assay

An auxiliary method for determination of chemosensitivity with the subrenal capsule assay (SRCA) was developed in which the specific activity of succinate dehydrogenase (SD) of tumor implanted beneath the renal capsule is measured. The appropriate conditions for measuring the specific activity of SD were determined. The chemosensitivity of tumors, derived from six xenograft lines originating from oral squamous cell carcinomas, to peplomycin (PEP), cisplatin (CDDP), and 5-fluorouracil (5-FU) were evaluated by the SRCA and the nude mouse assay (NMA). The chemosensitivity evaluated by NMA displayed a higher degree of correlation with that determined by the improved SRCA than with that determined by the conventional SRCA. The correlations between overall accuracy of prediction with the NMA and those with the conventional SRCA and the improved SRCA were 72.2% and 88.9%, respectively. These findings suggest that our new assay may be useful for evaluation of chemosensitivity in the SRCA.