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Aberrant methylation of promoter CpG that causes silencing of tumor suppressor genes (TSGs) may play a key role in the carcinogenesis of many cancer types. RASSF1A, regarded as a TSG, has been extensively studied in lung cancer and other malignant tumors, whereas RASGRF2 has only been reported to possibly play a role in the pathogenesis of pancreatic cancer cell lines. The aims of our study were to i) determine the methylation profile of RASGRF2 and ii) compare the methylation profiles of RASGRF2 with RASSF1A in lung cancer. We examined RASGRF2 expression by reverse transcription PCR and aberrant methylation of RASGRF2 by methylation-specific PCR in lung cancer cell lines. Loss of RASGRF2 expression was presented in 36% lung cancer cell lines while aberrant methylation of RASGRF2 was present in 30% (3/10) non-small cell lung cancer (NSCLC) cell lines and in 25% (1/4) small cell lung cancer (SCLC) cell lines. The concordance between loss of expression and aberrant methylation of RASGRF2 was 86% (12/14). RASGRF2 expression was restored after treatment with the demethylating agent, 5-aza-2'-deoxycytidine in all four cell lines tested that downregulated RASGRF2 expression. Among primary NSCLC, RASGRF2 and RASSF1A methylation was observed in 34% (39/114) and 39% (44/114) of cases respectively, while it was observed in only 7% (4/57) and none of the corresponding non-malignant lung tissue. There is no correlation between RASGRF2 and RASSF1A methyl-ation status. Both RASGRF2 and RASSF1A methylation did not associate with clinical characteristics. Frequent methylation and silencing of RASGRF2 in tumor cells may play an important role, different from that of RASSF1A, in the carcinogenesis of NSCLC. more...

Thymic carcinoma, which is a rare epithelial neoplasm of the thymus gland, is different from thymoma in its clinical and pathological features. To clarify the mechanism underlying the aggressive behavior of thymic carcinoma, we examined the clinicopathologic features, aberrant methylation patterns of the tumor suppressor genes, and epidermal growth factor receptor (EGFRs) mutation in both thymic carcinomas and thymomas. Clinical data of 11 thymic cancers and 13 thymomas were reviewed. Resected samples of 5 thymic cancers and 6 thymomas selected from 24 cases were used for methylation and mutation studies. Positive tumor markers were more frequent in thymic cancers than in thymomas (p=0.0233), and the methylation index, which reflects the overall methylation pattern, was significantly higher in thymic carcinomas (p=0.0053). No tumors showed a mutation of EGFR, KRAS, and HER2. Thymic carcinoma is distinct from thymoma not only with respect to clinicopathological features, but also aberrant methylation patterns of the tumor suppressor genes. more...

For non-small cell lung cancer (NSCLC), which is refractory for both platinum-based chemotherapy and docetaxel, no standard regimen has yet been established. We conducted a phase I study of a combination of vinorelbine and gemcitabine as third-line chemotherapy for refractory NSCLC to determine both the maximum tolerated dose (MTD) and the recommended dose (RD). Twenty patients with NSCLC refractory for both platinum and docetaxel were enrolled, and all patients were eligible for this phase I study. Cohorts of three to seven patients received vinorelbine at doses ranging from 20 to 25 mg/m(2), and gemcitabine at doses ranging from 600 to 1000 mg/m(2), on days 1 and 8 every 3 weeks. The dose-limiting toxicities were treatment delay, serum gammaGTP elevation, diarrhea and cerebral infarction, which were resolved without serious sequela, and there was no treatment-related death. The MTD was vinorelbine at 25 mg/m(2) and gemcitabine at 1000 mg/m(2) and the RD was vinorelbine at 25 mg/m(2) and gemcitabine at 800 mg/m(2). The median overall survival time was 6.8 months for all 20 patients eligible. As third-line chemotherapy, the combination of vinorelbine and gemcitabine was feasible and promising for NSCLC which is refractory for both platinum and docetaxel. more...

Thymic carcinoma is a rare mediastinal neoplasm with a poor prognosis due to delayed diagnosis and highly malignant behavior. To evaluate 7 serum tumor markers and the outcome of treatment, 11 stage III-IVb thymic carcinomas undergoing multimodality treatment were reviewed. High levels of serum CYFRA21-1 were detected in 5 patients (45%) and correlated with the progression of disease. Of the patients, 6 underwent surgery. The median survival time was 38.4 months, and the 5-year survival rate was 15.6%. The metastatic stage (IVb) and treatment without resection were significantly associated with poorer overall survival (p=0.0034 and p=0.0041, respectively). Our data demonstrated that serum CYFRA21-1 may represent a potential new biomarker in thymic carcinoma. Stage may provide a basis for prognosis in stage III-IVb thymic carcinoma, and resection is one of the most important parts of multimodality treatment for advanced thymic carcinoma. Effective neoadjuvant treatment is therefore essential. more...