Phosphorylation of an exogenously expressed S904F mutant of CCDC6-RET in H1299 lung cancer cells, which do not express endogenous RET6, was maintained at a higher vandetanib concentration (half-maximal inhibitory concentration [IC50] = 2.6 μM) than that in the wild-type CCDC6-RET protein (IC50 = 0.57 μM) (Fig. 2a). This evidence concerns the gene RET and lung cancer.