A subset of LCNEC also harbors mutations of TP53 and RB1 genes (similar to SCLC), while small proportions of LCNEC may have MEN1 mutations as well as KRAS and STK11/KEAP1 mutations, typically seen in NSCLC and not SCLC. Here, KEAP1 is linked to large cell neuroendocrine carcinoma.