MSI can be identified by two methods [9]: immunohistochemistry (IHC)-based detection of MMR proteins (MLH1, MSH2, MSH6, and PMS2) in tumor cells or molecular assays using polymerase chain reaction (PCR) or next-generation sequencing (NGS) for the evaluation of alterations in the microsatellites. This evidence concerns the gene MLH1 and neoplasm.