For EGFR-mutant NSCLC transformation into SCLC, there are many responsible additional gene alterations, such as RB1 loss, TP53 mutations, PIK3CA, BRAF, WNK1, and ETV1 mutations, SPP1 upregulation, and REST inactivation (22–29). Here, RB1 is linked to non-small cell lung carcinoma.