KRAS Exon 3 and PTEN Exon 7 Mutations in Small-cell Lung Cancer.

Small cell lung cancer (SCLC) is recognized as one of the most aggressive and fatal malignant tumors. No significant improvement has been made to prolong the survival of SCLC patients. This study aimed to examine the mutation status of K-Ras (KRAS) and phosphatase and tensin homolog (PTEN) in SCLC patients in order to identify potential therapeutic targets for SCLC. Nineteen primary SCLC tumor specimens were enrolled in the study. Direct sequencing was performed to detect the mutations of KRAS exon 3 and PTEN exon 7 in the specimens. Kaplan- Meier and Cox regression analysis was performed to determine the overall survival (OS) of these SCLC patients. KRAS exon 3 mutation was found in 4 (21%) SCLC patients, and PTEN exon 7 mutation in only 1 (5%) SCLC patient. Kaplan Meier analysis showed that clinical stage and brain metastasis were significantly associated with OS (both P<0.05), but neither KRAS exon 3 mutation nor PTEN exon 7 mutation was significantly associated with OS (P>0.05). Cox proportional hazards regression model indicated that extensive stage of disease was the only independent negative prognostic factor for OS in SCLC patients. In conclusion, KRAS exon 3 and PTEN exon 7 mutations had no significant impact on OS of SCLC patients. Further study is still necessary to validate the molecular profiles of SCLC.