DNA topoisomerase type II alpha (Topo IIα) nuclear enzyme is associated with chemosensitivity, chemoresistance and cell proliferation in various neoplastic lesions. This study was performed to clarify whether the Topo IIα/Ki-67 labeling ratio (T/K ratio), which reflects Topo IIα expression level, has significant predictive value in determining response to chemotherapy in oral squamous cell carcinomas (OSCC). We retrospectively reviewed the case of 22 patients with OSCC treated with chemotherapy using a combination of cisplatin and 5-FU (CF therapy). Expression of Topo IIα and Ki-67 was examined by streptoavidin-biotin peroxidase using pretreatment biopsy specimens. A significant difference in the mean T/K ratio of the effective group and the ineffective group (P<0.005) was observed. Similar findings were found with regard to Ki-67-LI values (P<0.01). However, the difference was larger in T/K ratios than in Ki-67-LI values. No difference was observed between the chemotherapeutic effects in Topo II α-LI. The present results suggest that T/K ratios may lead to improved prediction of the effect of CF therapy.

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Chronic betel quid chewing has a strong correlation with oral cancer. In order to examine relationship of p53 and p16, and the prevalence of human papillomavirus (HPV), we studied p53, Bax, p16^INK4a, Rb and HPV prevalence using forty-seven cases of betel quid associated oral squamous cell carcinoma (OSCC) in Myanmar. HPV was detected by polymerase chain reaction (PCR), using primers MY09 / MY11 and L1C1 / L1C2 and L1C2m. Immunohistochemically, 59.6% were p53-positive and Bax-negative, and 68.0% were p16^INK4a-negative and Rb-positive. HPV DNA was detected in only 14.9% of all OSCCs. The expression of p53/Bax relation (P<0.01) and p16^INK4a/Rb relation (P<0.001) were found in betel quid associated OSCCs when compared with normal mucosa. Therefore, betel quid plays a critical role in oral carcinogenesis in Myanmar.

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To clarify the possible role of tumor angiogenesis, vascular endothelial growth factor (VEGF) and microvessel density (MVD) were immunohistochemically examined in tongue squamous cell carcinomas as well as in normal tongue mucosa and squamous cell carcinoma-adjacent tongue mucosa. Immunoreactivity for VEGF was detected in epithelial cells of several nonneoplastic tongue mucosa tissues and most tongue squamous cell carcinomas, indicating that this angiogenic factor acted on endothelial cells via the paracrine mechanism. VEGF expression in squamous cell carcinoma-adjacent tongue mucosa was greater than that in normal tongue mucosa, and VEGF expression in tongue squamous cell carcinomas was much higher than in squamous cell carcinoma-adjacent tongue mucosa and normal tongue mucosa. Up-regulation of VEGF might be associated with neoplastic or malignant change of epithelial cells in tongue mucosal tissues. MVD in tongue squamous cell carcinoma was higher than that of squamous cell carcinoma-adjacent tongue mucosa and normal tongue mucosa, indicating increased demands for blood supply in the carcinoma tissues. The association of VEGF expression, MVD and clinicopathological parameters of tongue squamous cell carcinomas was not statistically obvious; however, VEGF expression was slightly larger according to T stages or nodal metastasis.

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Oral squamous cell carcinoma (SCC) is relatively uncommon in patients less than 40 years of age. Of 411 patients with oral SCC treated, 27 patients (6.6%) were less than 40 years of age. These cases of young age were compared with those of older age concerning their clinical characteristics and outcome. The five-year overall survival rate was 92.6% for young and 68.8% for older patients, respectively (P = 0.027). Using logistic multivariate regression analysis, including age, gender, primary site, TN category and treatment modality, only TN category and treatment modality were significant and independent predictive variables for recurrence, but age was not (P < 0.05). It was concluded that better prognosis observed in young patients with oral SCC was significantly determined by their characteristics of TN category and treatment modality, but not by their age.

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A case of primary localized amyloidosis of the angle of mouth is reported. The patient was a 64-year-old woman, and physical examination revealed a lesion about the size of a grain of rice on the left angle of mouth. Diagnosis was made by histopathologic study of surgical specimen. Immunohistochemical study of the infiltrated plasma cells suggested that the origin of amyloid protein to be amyloid L protein. Systemic amyloidosis was ruled out based on clinical and laboratory examination. At follow up 15 months later, no recurrence was observed and no symptoms were present.

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