p53 protein expression was present in 15/21 (71.4%) of SCLC, and in 15/28 (53.6%) of LCNEC, while 9/24 (37.5%) of SCLC and 16/27 (59.3%) of LCNEC expressed RB1. This evidence concerns the gene RB1 and large cell neuroendocrine carcinoma.