LCT and small cell lung carcinoma: In any case, according to the branching evolutionary path of EGFRM+ LAC transforming to SCLC described by Lee et al. [200], the TKI-resistant SCLC clones emerged earlier and at much higher frequency from a founder LAC with complete (homozygous) inactivation of the tumor suppressor genes RB1 and TP53 at baseline as compared to LACs with intact p53 and Rb1 function.