Immunohistochemical Expression of Programmed Death Ligand 1(PDL1) in Endometrial Carcinoma and Its Relation to CD4 and CD8 Positive Immune Cells.

Abstract

Endometrial cancer (EC) is the most common cancer of the female genital tract. Egypt showed a significant increase in incidence lately of which 25% were premenopausal. Advanced or recurrent disease are mostly unresectable and the traditional adjuvant therapy give modest results with devastating side effects. Late discoveries of immune checkpoint inhibitors have produced promising results. Programmed cell death 1 (PD1) is an immune inhibiting receptor on surface of lymphocytes, which plays critical roles in maintaining immunological self-tolerance. There are two ligands for this receptor, PDL1 and PDL2. PD-L1 is expressed on tumor cells; attaches to PD1, allowing tumor cells to escape from the host immune response. Its prognostic significance in various tumors is controversial and its significance in ECs has just begun to be investigated. Therefore, we investigated the relationship between PDL1 expression and different clinicopathologic parameters in EC cases and its correlation with CD4 and CD8 immune cells, in order to identify the predictive biomarkers for the outcome by immune therapy. Hundred, paraffin tissue blocks of EC cases were collected and stained with antibodies against PDL1,CD4 and CD8. PDL1 was positive in 67% of cases in tumor cells and in 61% of cases in immune cells. CD4 and CD8 were expressed in 79% of cases. Statistically significant correlations were observed between PDL1 expression and patients mean age, LVSI, TILS score and CD4+/CD8+ expression. Those variables can stratify candidates who can benefit most from immunotherapy, or can be chosen for further high cost molecular investigations application.