Mismatch repair deficiency in young patients of reproductive age with endometrial cancer and atypical endometrial hyperplasia

Abstract

MPA therapy is widely administered to patients with early-stage endometrial cancer and atypical endometrial hyperplasia (AEH) who desire a fertility-preserving treatment modality. We examined the relationship between MMR protein expression and the effects of MPA therapy, risk of relapse, prognosis, and familial history in 21 patients. We observed MMR deficiency in 7 patients (MLH1: 4, PMS2: 5, MSH2: 2, and MSH6: 2). All patients with lymph node metastasis or who died had MLH1 deficiency. In 13 of 21 patients, we performed MPA therapy for fertility preservation and confirmed MMR deficiency in 2. After the initial treatment, ovarian cancer developed in 2 patients, one of whom had Peutz-Jeghers syndrome. Due to the small sample size of this study, we found no significant association between MMR deficiency and the effects of MPA therapy or the risk of relapse. Many young patients with endometrial tumors may have inherited diseases, although not necessarily with MMR deficiency. Therefore, clinical assessment considering their past history and family history should be performed prior to each treatment. Our findings will serve as a catalyst for future studies with larger sample sizes.