Familial factors and genetic predisposition to cancer: population studies.

Hereditary cancer-prone families provide one of the most powerful and potentially cost-effective models for cancer prevention and control. The public health impact of this problem is enormous when considering that between 5 to 10% of the total cancer burden is hereditary. At least 200 well-defined hereditary cancer syndromes have been identified. In spite of its impact, attention to family history of cancer is often given short shrift and, consequently, clinical expertise in identifying hereditary forms of cancer is exceedingly limited. This may change as a result of recent advances in biomolecular genetics which, predictably, may lead to the cloning of many of these deleterious genes so that diagnostic and even pharmacologic and preventive potential may be achieved. We focus attention on advances which have been made in the recognition of hereditary forms of carcinoma of the breast and colon. Emphasis is given to biomarker research and the recognition of the distinctive natural history of these hereditary cancer syndromes. This will then enable surveillance and management strategies to be more effectively targeted.