OBJECTIVETo detect the frequency of ROS1 gene rearrangement in non-small cell lung cancer ( NSCLC) patients by FISH, and to analyze the relationship between ROS1 gene rearrangement and clinical features (including age, sex, stage, histology, smoking history) with NSCLC.

METHODSThe ROS1 gene rearrangement in histological sections of 1 652 NSCLC tissues was detected by FISH. The extracted RNA was amplified and the sequences were analyzed by Sanger sequencing for ROS1-positive samples.

RESULTSROS1 rearrangement was identified in 53 specimens (3.2%) from the 1 652 NSCLC tissues. Among these positive cases, 15 were CD74-ROS1, 13 were SLC34A2-ROS1, 13 were SDC4-ROS1 and 12 were TPM3-ROS1. The frequency of ROS1 rearrangement was significantly higher in never-smoking patients (49 cases) than in smokers (4 cases) (P < 0.05). Patients with ROS1-positive NSCLC tended to be younger and there was no significant difference in sex (P > 0.05). All of the ROS1-positive samples were adenocarcinomas, with a tendency toward higher clinical stage (P < 0.05).

CONCLUSIONSROS1 rearrangement has diversity, and may be defined as a new molecular subtype of NSCLC. ROS1 rearrangement tends to occur in younger, and never-smoker lung adenocarcinoma patients.