OBJECTIVE: To evaluate the mutation rates of homologous recombination repair (HRR) genes and the impact of these mutations on the clinical characteristics of metastatic endometrial cancer (EC). METHODS: Somatic DNA from 895 patients with metastatic EC in the Memorial Sloan Kettering-Metastatic Events and Tropisms cohort was assessed for mutations in 10 HRR genes ( RESULTS: Somatic mutations in HRR genes were detected in 106 (11.8%) patients with metastatic EC. Compared with nonmutation carriers, a greater proportion of carriers had endometrioid carcinoma (76.4% vs. 50.3%, p<
0.001). Regarding the TCGA classification, the proportions of the CONCLUSION: Somatic HRR mutations are detected in 11.8% of metastatic EC. Compared with noncarriers, HRR mutation carriers in metastatic EC have higher proportions of endometrioid carcinoma,