Lack of association between deficient mismatch repair expression and outcome in endometrial carcinomas of the endometrioid type

Abstract

Objective: Endometrial carcinomas of the endometrioid type (EEC) are associated with a good prognosis. However, about 20% of them recur and new prognostic markers are needed. Microsatellite instability (MSI), associated with mismatch repair (MMR) deficiency, is a frequent alteration in EECs that has been associated with prognosis. However, its prognostic impact on EECs remains unclear. The aim of the present study was to clarify the relationship between MMR deficiency and outcome in a large cohort of well classified EECs.

Methods: A total of 212 EEC samples were analyzed by immunohistochemistry for the MMR genes MLH-1, MSH-2, MSH-6 and PMS-2. Kaplan-Meier survival analysis and log-rank tests were performed to study the prognostic significance of dMMR taking into account clinical and pathological parameters.

Results: We observed no association between MMR deficiency and OS or PFS in our 212 EEC patients (p-value=0.6565 and 0.4380, respectively). When we performed the analysis in different FIGO-stage groups, we did not find association between MMR and OS or PFS in stages I, I/II or III/IV. When we analyzed the specific group of patients with lymphatic invasion separately, MMR expression was not associated with OS or PFS either.

Conclusions: MMR deficiency does not seem to be a good prognostic marker in endometrioid type endometrial carcinomas.