Abstract
Evaluating the therapeutic response and survival of lung cancer patients receiving first-line chemotherapy has always been difficult. Limited biomarkers for evaluation exist and as a result histology represents an empiric tool to guide therapeutic decision making. In this study, molecular signatures associated with response and long-term survival of lung cancer patients receiving first-line chemotherapy are discovered. Whole-exome sequencing is performed on pretherapeutic tissue samples of 186 patients [145 non-small cell lung cancer (NSCLC) and 41 small cell lung cancer (SCLC)]. On the basis of genomic alteration characteristics, NSCLC patients can be classified into four subtypes (C1-C4). The long-term survival is similar among different subtypes. SCLC patients are also divided into four subtypes and significant difference in their progression free survival is revealed (P < 0.001). NSCLC patients can be divided into three subtypes (S1-S3) based on TMB. A trend of worse survival associated with higher TMB in subtype S3 than in S1+S2 is found. In contrast, no significant correlations between molecular subtype and therapeutic response are observed. In conclusion, this study identifies several molecular signatures associated with response and survival to first-line chemotherapy in lung cancer.