Familial Cancer: A review on hereditary cancer traits with special regard to colorectal carcinoma

Abstract

Abstract

Substantial evidence supports the two-step mutation hypothesis by Knudson in human carcinogenesis. In inherited cancer traits the first mutation is thought to be inherited, but this oncogene acts recessively, and the cancer develops only after a second mutation, where the normal allele of this gene, the antionco-gene, is lost. The most recent discovery in the field of inherited cancer diseases, is localization of the gene for adenomatous polyposis on chromosome 5. Inherited cancer traits may occur in greater frequency than was previously known. One example is the cancer family syndrome (CFS), where colorectal carcinoma is transmitted in an autosomal dominant mode. Clinical characteristics of CFS include early age of onset (mean about 40 years), high risk of metachronous colon tumours (32 to 54% in 10 years) and proximal predilection of the colon tumours. The frequency of CFS is at least 5% of all colorectal carcinomas, and this trait may present one opportunity for cancer screening programmes like familial adenomatous polyposis. Identification of CFS patients remains a problem even when careful family history is taken, and a specific biomarker for CFS is urgently needed.