Molecules such as p16, CDK-4, E2F-1, p21, and p53 are reported to be overexpressed in salivary gland tumours: p27 is overexpressed in adenocarcinomas but not in ACC; p63 is expressed differently depending on the isoform; Bub1 and STAT3 are overexpressed in malignant tumours; the role of the cyclin D1 remains unclear. The gene discussed is CDK4; the disease is cancer.