75 The association of molecular changes with oncological results on low and intermediate risk endometrial cancers and the effect of new risk groups created by combining histopathologİcal data and molecular changes on clinical management

Introduction/Background This study's objectives include identifying various molecular subgroups in endometrioid-type endometrial cancers (EEC), investigating the association between molecular profile and clinicohistopathological data and determining low and intermediate risk EC groups by merging the data collected. Methodology Retroprospective analysis was performed on 1040 individuals who underwent surgery and were monitored between January 2000 and June 2022. Out of 900 EEC cases, 72 had recurrence. Matching was done between the patient groups with tumor recurrence (n=62) and those without (n=52). The 9th, 13th, and 14th exons of the POLE gene were examined with Sanger sequencing to determine the mutation status in the tumor tissue blocks, as well as P53, MMR proteins (PMS2, MSH1, MSH2, MSH6), CTNNB1 and L1CAM antibodies by immunohistochemical staining methods. Results POLE-mut%7, MMR-d%48, p5mut 10,5%, and NSMP 42% were identified among the cases. POLE and P53 mutations were found more frequently in high grade tumors (p4 cm, LVSI positive, and MI >50% (pConclusion Stage 1–2 POLEmut cases should be included in the low risk group regardless of LVSI status. On the other hand, instances with LVSI-detected p53-mutation in stage Ib-II and grade III cases could be classified as high risk, whereas those without LVSI could be classified as medium-high risk. Disclosures The authors have nothing to disclose.