Model Hereditary Cancers of Man

Abstract

Publisher Summary This chapter discusses different model hereditary cancers of man such as retinoblastoma and Wilms' tumor. About 30% of persons with retinoblastoma are affected bilaterally. Therapeutic success is such that many of them have survived, often with one useful eye, and have produced offspring. One-half of these offspring acquire the tumor, from which it was concluded that virtually all bilateral cases are prezygotically determined. Because most bilateral cases have unaffected parents, it has been further concluded that they result from new, mutations in parental germ cells. Because some unilaterally affected survivors have affected offspring, it can be estimated that approximately 40% of all cases are germinal, implying that 60% are somatic in origin. The numbers of tumors in heterozygous carriers follow a Poisson distribution, with a mean of 3-4. The location of a gene responsible for the heritable cases of Wilms' tumor with no constitutional karyotypic abnormality has not been accomplished, but a category of constitutional deletion has been identified. The hereditary cancers of man may be induced by mutations in a set of differentiation genes, and the corresponding nonhereditary cancers may entail somatic mutations in the same genes. A single mutation is not sufficient for oncogenesis and it may be considered that the genes are recessive with respect to malignancy, in contrast to the apparent dominance of virus-like oncogenes.