The study of RET rearrangement in advanced primary non-small cell lung cancer and associated metastatic lesions

Abstract

Background: ALK rearrangement in non-small cell lung cancer (NSCLC) patients has recently been identified as a driver gene and benefited from crizotinib treatment. However, no data are available for ALK rearrangement NSCLC about the relationship between primary and metastatic patients. The aim of this study was to examine the positive rate of ALK rearrangement in primary and metastatic NSCLC, and to investigate their relationships. Methods: From January 2013 to May 2015, 384 cases of primary NSCLC, 246 cases of matched metastatic tumors, and 47 cases of normal lung specimens, as the control group, were collected in our multicenter. The positive rate of ALK rearrangement among the NSCLC population was established, and thus the consistency of ALK rearrangement in advanced primary NSCLC and associated metastases and the relationship between ALK rearrangement and clinical data was analyzed. Results: The positive rate of ALK rearrangement on primary tumor was 11.46% (44/384). For those 246 paired cases, the positive rate on primary tumor was 10.98% (27/246), with that of metastases 7.32% (18/ 246). Among the 246 cases, there were two cases whose metastases were positive but primary tumors were negative and 11 case whose primary tumors were positive but metastases were negative. Positive rate of ALK rearrangement was higher in the primary lesions than in metastases. It was of statistical significance between the two groups (χ2 = 112.208, P < 0.001). The positive rate of primary tumors could be predicted by metastases (κ = 0.683, P < 0.001). The sensitivity was 59.26% (16/27) and the specificity was 99.09% (217/219). Conclusions: The metastases of NSCLC can predict ALK rearrangement of the primary lesions. It can be used as an alternative means for metastases to detect ALK rearrangement which are not readily available.