ARID1A and mismatch repair cancer syndrome 1: In addition, somatic mutations in ARID1A, CDC73, and SMARCA4 gene were co‐occurrent with germline mutations of the MMR pathway (Fig. 4B); previous studies have found that mutations in ARID1A [53], CDC73 [54], and SMARCA4 [55] are enriched in microsatellite instable tumors, which supports our findings and demonstrates these genes may be the targets of MMR deficiency.