The other patient with isolated MSH6 loss, and the 5 cases with combined MLH1/PMS2 loss in the absence of MLH1 gene hypermethylation (both histo-molecular patterns highly suggestive of Lynch syndrome19), were classified as highly suspected Lynch syndrome; unfortunately, germline tests confirming constitutional MMR gene mutation were not available for these 6 patients. This evidence concerns the gene MLH1 and Lynch syndrome.