The identification of high risk populations.

This presentation is concerned with the early identification of individuals at increased risk for cancer of the large intestine. To facilitate this work we developed a comprehensive register of individuals at high risk for colorectal cancer at Memorial Sloan-Kettering Cancer Center. The high risk groups are characterised by an hereditary predisposition to colorectal cancer, as suggested by familial associations or early ages of onset of neoplasia, or by the presence of a previous disease of the large intestine believed to be associated with premalignancy. Recent information on the biological characteristics of colonic mucosa, and related findings in individuals with increased susceptibility to colorectal cancer, are summarised in this review. Particular reference is made to proliferate abnormalities that develop during early stages of neoplastic cell transformation, and to new methods of measurement which facilitate the identification of early abnormalities.