Evaluation of colorectal cancers for Lynch syndrome: practical molecular diagnostics for surgical pathologists.

Lynch syndrome is the most common inherited colorectal cancer syndrome, accounting for 2-4% of all colorectal cancer cases. This review focuses on the tissue workup of Lynch syndrome, including methods to determine whether or not a tumor is mismatch repair deficient, and whether a mismatch repair-deficient tumor is sporadic or Lynch syndrome-associated. Strategies for determining which tumors to test and how best to implement a Lynch syndrome screening program are also discussed, as well as potential developments in the future.