High predictability for identifying Lynch syndrome via microsatellite instability testing or immunohistochemistry in all Lynch-associated tumor types

Lynch syndrome is an inherited cancer-prone syndrome identified in ~3% of all colorectal cancer (CRC) patients and ~2% of all endometrial cancer (EC) patients (1-3). It is defined by identification of a germline mutation in one of the DNA mismatch repair (MMR) genes (MSH2, MLH1, MSH6, PMS2, EPCAM) whose proteins function to maintain replication fidelity of DNA prior to mitosis, and sets it apart from other hereditary non-polyposis colorectal cancer (HNPCC) syndromes such as Familial Colorectal Cancer Type X and Polymerase Proofreading Polyposis syndrome (3).