Image analysis of tumor infiltrating lymphocytes components of EGIST microenvironment

Abstract

Extra gastrointestinal stromal tumor (EGIST) are sarcomas originating from Cajal like cells. They are prone to events triggering inflammation. Aimes and Objectives: To describe into a retrospective study, the intratumoral lymphocytes in a series of EGIST and correlate their density with the proliferation index and morphology. Methods: Using antibodies against CD5, CD20, CD45, we demonstrated lymphoid cells and structures by using immunohistochemical methods. Slides were analyzed using QuPath for tumor-infiltrating lymphocyte (TIL) density. Tertiary lymphoid structures (TLS) were reported per sample. Statistical analysis was done using the Kruskal-Wallis corrected test and the Pearson coefficient. Results: We selected 22 cases with an average age of 51 years. Histologically, the batch was composed of fusiform, epithelioid, and mixed EGIST (63%; 14% and 23%). Numerical analysis of immunohistochemical stains showed an average Ki67 of 19%. The average TIL density of T and B cells was 1.6*103 cells/mm2 and 263 cells/mm2. The TLS have an average of 2.41 households/sample. The correlation between T and B cell density and between TIL with Ki67 shows p > 0.05 in our EGIST series. The correlation between EGIST histological variants with TIL type density resumed a p>0.05. Conclusion: TIL cell densities are independent histological parameters for EGIST. The TIL arrangement is inhomogeneous in EGISTs; T cells predominate.