RB1 and small cell lung carcinoma: Inactivating mutations in the tumor suppressor genes TP53 and RB1 were detected at a frequency of only 4.3% in SCCC samples (Supplementary Fig. 27a and Supplementary Data 18 and 19), while universal bi-allelic inactivation of TP53 and RB1 was found in nearly all small cell lung carcinoma (SCLC) samples20.