862P Prognostic role of CD3, CD4, CD8 and FOXP3 positive populations in early-stage endometrial carcinoma

Abstract

using immunohistochemistry for p53 (p53 wild-type "p53wt" or p53 aberrant "p53abn" expression) and mismatch repair (MMR) proteins (MLH1, PMS2, MSH2, and MSH6), considering MMR deficiency (MMRd) when a loss of MMR nuclear staining for at least one protein was identified. Identification of POLE mutations (POLE-EDM) was made by sequencing exons 9e14. Only pathogenic variants described in COSMIC database were considered for further analysis. Clinicopathological variables and survival ([RFS, relapse free survival; OS, overall survival]) correlations were assessed by the Kaplan Meier method and log rank.Results: A cohort of 54 patients fulfilled clinical and pathological criteria. Distribution by histological subtype was: endometrioid (46.3%), serous (33.3%), undifferentiated (11.1%), mixed (5.6%), and clear cell (3.7%). Molecular profile was fully evaluable in 49 samples: MMRd (26.5%), POLE-EDM (12.2%), p53wt (22.5%), p53abn (38.8%). Regardless of molecular subtype, 5 year relapse rate was: POLE 0%, MMRd 31.6%, p53wt 35.7%, p53abn 48.9% (p¼0.23), and 5 year OS rate was: POLE-EDM 100%, MMRd 76.2%, p53wt 48% and p53abn 38.5% (p¼0.18). Considering only endometrioid subtype, there was a statistically significant correlation of the molecular classification with 5 year OS (p¼0.02).Conclusions: To our knowledge, this is the first series that has evaluated the molecular classification focused on early-stage HG-EC, including all histologies. Patients with POLE-EDM have an excellent prognosis, with no relapses in this subgroup, whereas patients with p53abn have the worst prognosis. The application of molecular classification in daily practice could be useful in a better design of adjuvant therapy.Legal entity responsible for the study: The authors.