Public health perspectives on testing for colorectal cancer susceptibilitygenes

Context: About 131,600 new cases of colorectal cancer will be diagnosed in the United States in 1998. About 27,900 men and 28,600 women will die from colorectal cancer in 1998. Mutations to the hMSH2 gene on chromosome 2p and to the hMLH1 gene on chromosome 3p have been identified as causes of color ectal cancer. These mismatch repair genes, which have recently been cloned, account for most cases of hereditary nonpolyposis colorectal cancer (HNPCC ), one of the most common cancer susceptibility syndromes known. The carrie r frequency of hMSH2 and hMLH1 gene mutations in the U.S. population is unk nown. An ardenomatous polyposis coli (APC) gene variant (I1307K allele), wh ich was recently reported in I in 17 Ashkenazi Jewish persons, may double t he risk for colorectal cancer in that population. Conclusions: The use of genetic tests for susceptibility to cancer of the c olon and other sites needs careful scrutiny. Several issues must be address ed before such tests can be recommended for population-based prevention pro grams. For example, the screening of population subgroups raises concern ab out potential discrimination and stigmatization. Before genetic tests for c olorectal cancer are incorporated into future programs, the safety, effecti veness, and quality of these tests must be evaluated.