RB1 and small cell lung carcinoma: SCLCs are genetically driven by loss of function (LOF) alterations in tumor suppressor genes RB1 and TP535, with distinct expression patterns of certain TFs or transcriptional regulators leading to four molecular subtypes (SCLC-A, SCLC-N, SCLC-P, and SCLC-Y (YAP1))6.