Identification of Lynch Syndrome in Patients with Endometrial Cancer Based on a Germline Next Generation Sequencing Multigene Panel Test.

We aimed to investigate the prevalence and relative contributions of LS and non-LS mutations in patients with endometrial cancer in Korea. We retrospectively reviewed the medical records of 204 patients diagnosed with endometrial cancer who underwent a germline next generation sequencing multigene panel test covering MLH1 , MSH2 , MSH6 , PMS2 , and EPCAM at three tertiary centers. Thirty patients (14.7%) with pathogenic mutations (12 MLH1 ; 6 MSH2 ; 10 MSH6 ; 2 PMS2 ) and 20 patients (9.8%) with 22 unclassified variants (8 MLH1 ; 8 MSH2 ; 2 MSH6 ; 3 PMS2 ; 1 EPCAM ) were identified. After excluding four close relatives of a proband, the prevalence of LS was 13.0% (26/200). Patients with LS were more likely than those with sporadic cancer to be younger at diagnosis (48 vs. 53 years, p = 0.045) and meet the Amsterdam II criteria (66.7 vs. 3.5%, p < 0.001). Non-endometrioid histology was more prevalent in patients with MSH6 or PMS2 mutations (41.7%) than those with MLH1 or MSH2 mutations (5.6%, p = 0.026). In this pre-selected cohort of endometrial cancer patients who underwent next generation sequencing, the prevalence of LS was 13%, thus supporting the use of gene panel testing for endometrial cancer patients.