Prospects for cancer control and prevention through genetics.

At the cellular level, cancer is a genetic disease and, in populations, most cancers have genetic, congenital or familial determinants. Virtually all malignant neoplasms likely have cytogenetic abnormalities and some constitutional cytogenetic syndromes are complicated by cancer. Of 4344 known or suspected mendelian traits in human beings, 338 (8%) have neoplasia as a feature or a complication; 25% of preneoplastic genes have been mapped to specific chromosomes. Certain syndromes of familial aggregations of cancer have been recognized and many remain to be delineated; they may have genetic and environmental determinants. A National Institutes of Health workshop in 1986 proposed strategies for controlling cancer through genetics in four areas: clinical practice, educational and administrative measures, research needs, and ethical issues. Demonstrations of the feasibility of implementing the clinical guidelines are needed but will require the collaboration of clinical geneticists with medical oncologists.