CDKN2A and carcinoma: In smoking-associated carcinomas, mutations with loss of function of TP53 and inactivation of the CDKN2A gene, which encodes the p16 tumour suppressor protein, are almost universally demonstrated, together with frequent copy number alterations, including amplifications of 3p26/28 and 11q13—areas that harbour important oncogenes such as CCND1, which encodes cyclin D1.