The Prognostic Significance Of Microsatellite Status And Its Relationship With Tumor-Infiltrating Lymphocyte In Endometrial Cancer

Objectives: The relationship between the microsatellite status (MS), tumor-infiltrating lymphocytes (TIL) and prognosis is unclear in endometrial cancer. We aim to examine the impact of MS and TILs on prognosis in patients with endometrioid type EC. Methods: The patients diagnosed with EC were retrospectively analyzed in the study. MS was evaluated by immunohistochemistry (INC) based on expression of MLH1, MSH2, MSH6, and PMS2 proteins. The patients were stratified according to TIL patterns. TILs were classified as intratumoral (iTIL), stromal (sTIL), and peritumoral TILs (pTIL). Results: A total of 91 patients with different stages of endometrioid type EC. In terms of MS, 58 patients were microsatellite stable (MSS) and 33 patients were microsatellite instable (MSI). pTIL score was higher in patients with MSI than patients with MSS (P < 0.0001). We observed significant correlation between pTIL infiltration and MSI status. There was no statistically significant difference between the survival of patients with MSI and MSS irrespective of disease stage; median OS rates were 96 and 136 months, respectively (P = 0.151). Survival difference was not significant between patients with MSI and MSS early-stage disease: OS rates for patients with MSI and MSS were 95 and 139 months, respectively (P = 0.087). Conclusion: Our study identified a relationship between the extent of TIL infiltration and MSI status and reveals that EC with MSI attracts more immune cells to the tumor micro-environment. However, we could not find prognostic effect of microsatellite status in patients with EC.