After one decade of molecular genetic studies, little doubt remains that
cancer is a
genetic disease. While mutations in somatic cells may cause
cancer, they don't carry forward to the next generation. In fact, most
cancers arise in this way. In some individuals mutations in
cancer related genes may be present at the constitutional level, inherited from one of the parents. An individual who carries a mutant allele of an inherited cancer gene has a variable risk of
cancer that is influenced by other genetic and non-genetic factors (such as other cellular genes, dietary, lifestyle, and environmental factors). Collectively, the syndromes affect about 1% of
cancer patients. During the past decade about 25 different
cancer susceptibility genes have been reported to be linked to the known
hereditary cancer syndromes. Over the period of the last three to five years, studies of the specific mutations responsible for these syndromes and the cellular signaling pathways disrupted by the
mutant proteins have begun to provide unprecedented insights into the molecular origin and pathogenesis of inherited and sporadic forms of
cancer. This article reviews the
cancer susceptibility genes and
cancer syndromes, particularly those associated with common
malignancies (breast, prostate and
colorectal carcinomas). Results of the mutation analysis in BRCA1 and BRCA2 genes of Hungarian breast/
ovarian cancer families will be briefly discussed. These data indicate a strong founder effect for some mutations of BRCA1 gene in Hungary. As a results of recent publicity of discoveries of molecular genetics--particularly those related to common
malignancies--due to publicity in the scientific and the lay press awareness and demand for predictive
DNA tests have dramatically increased worldwide over the past 3 years. The author, as a member of the
Breast Cancer Linkage Consortium, shares the consensus view that genetic testing and genetic counseling for
cancer risk together with surveillance and management should for the present be offered only through specialist clinical genetic departments as part of a research evaluation.