ROS1 gene rearrangement and clinicopathological characteristics in Chinese NSCLC patients

Objective: Since Rikova et al. reported c-ros oncogene 1 (ROS1) rearrangements in non-small cell lung cancer (NSCLC) in 2007, data on the clinicopathological characteristics of ROS1-positive patients in China are scarce. We aim to examine the correlation between clinicopathological characteristics of NSCLC patients and the frequency of ROS1-rearrangements. Methods: The cancer tissues of 1720 patients with NSCLC were analyzed using fluorescence in situ hybridization (FISH) assay to assess the presence of ROS1 gene fusions. Polymerase Chain Reaction (PCR) direct sequencing was performed to identify the fusion genes in positive tissues. Clinicopathological characteristics of the patients and the corresponding frequency of ROS1-rearrangement were analyzed. Results: Among the 1720 NSCLC patients, 31 (1.8%) were tested positive for ROS1-rearrangement. Compared to the ROS1negative group, they were significantly younger and more likely to be never-smokers (each P<0.05). All of the ROS1positive tumors were adenocarcinomas, and tend to be higher grade cancer (P<0.05), however there was no significant preference in gender (P>0.05). Four ROS1 fusions were observed in the samples, they were CD74-ROSl (n=9), SLC34A2-ROSl (n=7), SDC4-ROSl (n=8) and TPM3-ROSl (n=7). Conclusions: ROSl-rearrangements were recognized in 1.8% of the Chinese NSCLC patients studied, similar to the prevalence of 1-2% that had been reported. The clinicopathological characteristics of these patients were clearly associated with ROS1-rearrangements. Specifically, ROS1-rearrangements were significantly more prevalent in the younger and never-smoking lung adenocarcinoma patients.