Rektman et al. [23] showed that three LCNEC subtypes could be considered: (1) “NSCLC-like” defined by TP53 and KRAS/STK11/KEAP1, (2) “SCLC-like” based on concurrent TP53 and RB1 mutations, and (3) “Carcinoid-like” with MEN1 mutations. This evidence concerns the gene RB1 and small cell lung carcinoma.