Deregulated expression of cell cycle promoting cyclins, often resulting from specific tumour-associated gene amplification, represents a common mechanism leading to loss of cell cycle control, as well as genetic loss or transcriptional downregulation of cellcycle inhibitory factors, for example pRb and the CDK inhibitor p16INK4a (Pei and Xiong, 2005; Sharpless, 2005). The gene discussed is CDKN2A; the disease is neoplasm.