Mismatch Repair (MMR) Gene Mutation Carriers Have Favorable Outcome in Colorectal and Endometrial Cancer: A Prospective Cohort Study

Simple Summary: Germline and somatic deficiencies of mismatch repair proteins (MMRd) are related to colorectal and endometrial cancers, but the survival impact in Asian patients remains unclear. We investigated the prevalence and outcomes of patients with germline and/or somatic MMRd. Germline and somatic MMRd were determined by gene sequencing and protein staining of tumor samples, respectively. We found that colorectal and endometrial cancer patients with germline MMRd have favorable survival outcomes compared to those without, regardless of somatic MMRd status. These findings highlight the importance of germline genetic testing when tumor MMRd is detected.