Molecular changes in oral cancer may reflect aetiology and ethnic origin.

Oral cancer, although uncommon in the Western world, accounts for up to 40% of all malignancies in parts of India and South East Asia. Recognised aetiological agents of oral cancer include tobacco and alcohol. This paper reviews the spectrum of molecular changes found in oral squamous cell carcinomas from Western (U.K., U.S.A., Australia) and Eastern (India, S.E. Asia) countries. p53 mutations are common in tumours from the West (47%) but are infrequent in the East (7%). Tumours from India and South East Asia are characterised by the involvement of ras oncogenes, including mutation, loss of heterozygosity (H-ras) and amplification (K- and N-ras), events which are uncommon in the West. The possibility that these genetic differences reflect aetiology and/or ethnic origin is discussed.