Genetic determinants of cancer in man

Abstract

The clustering of cancers in individual families has long been recognised. In 18661 Broca described a family in which breast and gastrointestinal tract cancers occurred over four generations, and a dominant pattern of inheritance was recognised in retinoblastoma as long ago as 18962. However, with the exception of certain rare inherited conditions including retinoblastoma, neurofibromatosis and familial polyposis coli, where susceptibility to malignant disease is marked, genetic factors are generally considered to have much less importance than environmental factors. The study of cancer genetics in man may nevertheless be of considerable importance in understanding the fundamental nature of cancer, in developing cancer control programmes and in advising individual patients and their families. For some patients, possible increased risks of cancer in close relatives may cause considerable anxiety, and reassurances based on misconceptions are of little benefit. The present chapter aims to give a general overview of the more interesting aspects of genetic susceptibility to cancer in man, rather than to provide a detailed review of the literature. This will be used as the basis for a discussion of how a clinical and epidemiological approach to the study of human cancer genetics can be productive and worthwhile for experimentalists, medical practitioners and for patients and their families.