The trend observed in the test series was confirmed in the validation set, and when all MSI-H carcinomas of the two series are grouped together we observed that TGFBR2 and MSH3 mutations were significantly more prevalent in proximal than in distal (sigmoid and rectal) cancers (P = 0.00005 and P = 0.0000005, respectively). Here, TGFBR2 is linked to cancer.