Lei et al did not observe any significant difference in the efficacy of crizotinib between patients with the EML4-ALK fusion variant V3, V1 and other less frequent variants V2.[13] Yoshida et al found that the objective response rate (ORR) and disease control rate (DCR) of the EML4-ALK variant V1 responding to Crizotinib were 74% and 95% respectively, while other ALK fusions were 63% and 63%.[11] Another clinical study showed that the 2-year PFS of NSCLC patients with V3a/b was 26.4%, significantly lower than that other subgroups. This evidence concerns the gene ALK and non-small cell lung carcinoma.