Microsatellite instability in diverse populations

CN06-04

Colorectal cancer is a molecularly heterogeneous diagnosis. Broadly speaking, tumors can be categorized as having proficient or deficient DNA mismatch repair gene function. This is determined by tumor testing for "microsatellite instability" (MSI) and/or immunohistochemistry for the DNA mismatch repair gene products. Tumors that manifest high levels of MSI are strongly associated with right sided tumor location, female gender, older ages, or with HNPCC-Lynch Syndrome. Emerging evidence suggests that tumors with MSI have different prognosis and different response to chemotherapy agents. The incidence, site, stage, mortality of CRC have been described in many different populations and significant differences have been consistently identified. While originally attributed to societal factors such as access to health care, newer information suggests true biological differences. Available data on MSI in CRC diverse populations will be examined. In light of the emerging therapeutic implications of MSI, there is urgent need to more fully characterize CRC for MSI within all populations.