Microsatellite Instability in Colorectal Cancer What, How, When, and Why?

摘要

In this review, we briefly outline the definitions of DNA microsatellites, microsatellite instability (MSI), and explain DNA mismatch repair. Methods for testing MSI are described and compared with the complementary approach of immunostaining for DNA mismatch repair proteins, The use of such testing is then presented with respect to hereditary nonpolyposis colorectal cancer (HNPCC) and sporadic colorectal cancer, The role of the pathologist in suspecting the presence of MSI on the basis of morphologic criteria is discussed, The importance of distinguishing hereditary nonpolyposis colorectal cancer versus sporadic colorectal cancer with MSI is stressed, Finally, some medicolegal considerations are presented.