Single-nucleotide polymorphism rs41736 located in MET was significantly associated with prognosis of small cell lung cancer patients.

MET has been suggested to have an intimate relationship with small cell lung cancer (SCLC) and might be a promising therapeutic target. To date, relatively limited reports have been explored on MET mutational status in SCLC patients. To investigate the relationship between MET mutations and SCLC, 68 Chinese patients surgically treated for SCLC were enrolled. MET mutational analyses were performed in tumors, adjacent normal tissues as well as in lymph nodes with no metastasis nonadherent to tumor tissues using Sanger sequencing after PCR. The same mutation types were found in tumors, adjacent normal tissues as well as lymph nodes, including the only missense mutation N375S encoding semaphorin domain in exon 2 in 4 patients (5.9%), one single-nucleotide polymorphism (SNP) rs35775721: C>T also encoding semaphorin domain as heterozygous in 10 cases (14.7%) and another SNP rs41736: C>T encoding tyrosine kinase domain in exon 20 existing in 49 cases (72.1%). In survival analysis, the wild genotype CC-carriers of rs41736 conferred a significantly shorter progression-free survival (PFS) and overall survival (OS) compared to CT + TT-carriers (HR 0.455, 95% CI 0.229-0.904; HR 0.226, 95% CI 0.099-0.515, for PFS and OS, respectively) in limited-stage SCLC patients. We also found that the lymph node status was significantly associated with OS, and the shorter OS was present in positive group (HR 2.187, 95% CI 1.170-4.088). In this study, rs41736 polymorphism of MET was first found to be associated with prognosis of limited-stage SCLC patients and could be considered as a prognostic marker for limited-stage SCLC.