IHC for MMR proteins is commonly used as a screening test for Lynch syndrome, typically in combination with BRAF genetic testing and/or MLH1 promoter hypermethylation testing to exclude the majority of somatic deleterious variants.7 Thus, neoplasms with loss of MLH1 by IHC, negative for MLH1 promoter hypermethylation and/or negative for BRAF p.V600E, are recommended for germline MMR gene testing. This evidence concerns the gene MLH1 and Lynch syndrome.