Our algorithm had very high sensitivity (100% (95% CI 80.49, 100)) and specificity (98.25% (95% CI 90.61, 99.96)) for identifying MLH1-deficient IBD-CRC from all other cores in the TMA (i.e., MLH1-deficient IBD-CRC versus MLH1-proficient normal epithelium or MLH1-proficient IBD-CRC—there were no cores of MLH1-deficient normal epithelium, as expected). Here, MLH1 is linked to colorectal carcinoma.