RB1 and small cell lung carcinoma: Several abnormalities have been detected in SCLC, although none of them is specific for this tumour: frequent inactivation of TP53, RB1 and PTEN, 3p deletion in the region where the tumour suppressor gene FHIT is located, copy number gain in 7p 22.3, MYC amplification (involving several genes of the MYC family) (Voortman et al., 2010; George et al., 2015), low frequency of activating mutations in KRAS, EGFR and PI3KCA (Testa et al., 2018).