Hereditary and environmental risk factors; clinical and laboratory risk matters for head and neck, especially oral, cancer and precancer.

The continuing high incidence and mortality of squamous cell carcinoma of the upper aerodigestive tract in South Asia, parts of France and central Europe, together with a rising incidence and mortality from a lower base elsewhere in the Western world, stimulates continuing research on risk factors and risk markers. Tobaccos (smoked and smokeless), heavy alcohol consumption, and areca nut remain the dominant risk factors, with confirmation of the protective effects of diets rich in antioxidants. There is emerging evidence of a small, but real, risk associated with occupational and other air pollution, and with family, part of which may be hereditary. Markers in peripheral blood and saliva are underexploited. Clinical staging and histological grading methods continue to be refined, with improved prognostic value, much aided by newer and simpler methods for estimating cell proliferation and apoptosis. Data on the significance of viral genes are still inadequate, but there is good progress describing the epidemiology of chromosomal abnormalities and abberations of a growing list of oncogenes and tumour suppressor genes. Unfortunately, as yet, these have only limited longitudinal or prognostic data.