EGFR and small cell lung carcinoma: EGFR-mutant LUADs undergoing TKI treatment are known to be at unique risk of histological transformation to SCLC (Ferrer et al., 2019) particularly when p53 and RB are concurrently inactivated (Offin et al., 2019; Niederst et al., 2015; Lee et al., 2017).