7599 Background: Molecular abnormalities discovered in the last decade have led to a paradigm shift in the diagnosis and treatment of lung adenocarcinoma. But there have been few reports about molecular profiling of small cell lung cancers (SCLC). We conducted the Shizuoka Lung Cancer Mutation Study to analyze driver mutations in patients with thoracic SCLC malignancies. Methods: We collected molecular profiling data of SCLC from the biobanking system in conjunction with the clinic, including the pathology lab, where 23 mutations in 9 genes (EGFR, KRAS, BRAF, PIK3CA, NRAS, MEK1, AKT1, PTEN and HER2), EGFR, MET, PIK3CA, FGFR1 and FGFR2 amplifications, and EML4-ALK translocations were assessed using pyrosequensing plus capillary electrophoresis, qRT-PCR, and RT-PCR, respectively. To evaluate mutation status for SCLC patients, we collected patient characteristics data from medical records. Results: Between July 2011 and July 2012, fifty small cell lung cancer patients were assessed in our biobanking system. Patient characteristics were as follows: median age (range) 70 (43 - 82) years; male 82%; smoker 96%; limited disease/extended disease 56/44%; small cell carcinoma/combined small cell carcinoma with adenocarcinoma 94/6%; surgically resected snap-frozen samples 8, formalin-fixed paraffin-embedded samples 40 and pleural effusion 7. We detected driver mutations in 8 cases (16%). Mutations found: EGFR 1 (2%), KRAS 1 (2%), PIK3CA 2 (4%), AKT1 1 (2%), MET amplification 1 (2%), PIK3CA amplification 6 (12%). EGFR and KRAS mutation were found in combined small cell carcinoma with adenocarcinoma. No significant differences in age, sex, disease extent at diagnosis or smoking status were found between patients with mutations and those without mutations. But serum neuron-specific enolase (NSE) levels were significantly higher in patients without mutations (p=0.03). Conclusions: In our analysis, driver mutations were found in 16% of SCLC patients and PIK3CA amplification seemed to be relatively frequent in SCLC. Our results suggest that PIK3CA might become a target of treatment for SCLC patients.
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