Type I and II LCNECs harbor key genomic alterations and oncogenic mutations, which are commonly found in SCLC, lung adenocarcinoma or squamous cell carcinoma (e.g., in RAS genes, BRAF, NFE2L2, as well as in STK11 and KEAP1 in the case of type I LCNECS, and RB1 losses in the case of type II LCNECs). Here, RB1 is linked to small cell lung carcinoma.