Impact of Activation of EGFL7 within Microenvironment of High Grade Ovarian Serous Carcinoma on Infiltration of CD4+ and CD8+ Lymphocytes.

Background: It has been demonstrated that Egfl7 promotes tumor cell escape from immunity by downregulating the activation of tumor blood vessels. Aim: to analyze mRNA expression of EGFL7 within the tumor microenvironment of high-grade ovarian serous carcinoma and its association with a number of intraepithelial CD4+/CD8+ lymphocytes and ICAM-1 expression. Methods: qPCR analysis of EGFL7 mRNA in cancer cells and adjacent stromal endothelium microdissected from formalin-fixed paraffin-embedded tumors of 59 high-grade ovarian serous carcinoma patients, was performed. Infiltration of intraepithelial lymphocytes (CD4+/CD8+) and expression of ICAM-1 were evaluated by immunohistochemistry and compared between tumors with different statuses of EGFL7 expression. Results: EGFL7 was expressed in cancer cells (9/59, 15.25%), endothelium (8/59, 13.56%), or both cancer cells and adjacent endothelium (4/59, 6.78%). ICAM-1 was expressed on cancer cells (47/59, 79.66%), stromal endothelium (46/59, 77.97%), or both epithelium and endothelium (40 of 59, 67.8%). EGFL7-positivity of cancer cells and endothelium was associated with lower intraepithelial inflow of CD4+ (p = 0.022 and p = 0.029, respectively) and CD8+ lymphocytes (p = 0.004 and p = 0.031, respectively) but impact neither epithelial nor endothelial ICAM-1 expression (p = 0.098 and p = 0.119, respectively). The patients' median follow-up was 23.83 months (range 1.07-78.07). Lack of prognostic significance of EGFL7-status and ICAM-1 expression was notified. Conclusion: EGFL7 is activated in the cancer cells as frequently as in the endothelium of human high-grade ovarian serous carcinoma. Activation of EGFL7 in cancer cells and/or endothelial cells could negatively impact diapedesis regardless of localization.