RB1 and small cell lung carcinoma: When comparing the morphological features and considering the similar genetics and genomics characteristics between SCLC-Y (WT RB1) and LCNEC (WT RB1, WT KEAP1, WT STK11) subtypes, together with a low or absent expression of ASCL1 and NEUROD1, it has been suggested that these two lung cancer subtypes belong to a single entity [62]; thus, implying potential impact in molecular classification and clinical implications.