Comparing MSI/MMR-deficient and MSS/MMR-proficient samples, we found that the fraction of MMR-1, MMR-2, and MMR-3 signatures was strongly enriched in a cluster of microsatellite instable cancer samples (Wilcoxon rank-sum test P-values 1.7 × 10−51, 2.7 × 10−22­, and 9.8 × 10−29, respectively) (Fig. 3A, top left, 3C). Here, MFSD6 is linked to cancer.