Infiltration of Regulatory T Lymphocytes Impair Clinical Outcome in Ovarian Cancer Patients

Background: Ovarian carcinoma (OC) is one of the most severe and lethal cancers in women. Regulatory T (Treg) cells may participate in mediating a suppressive microenvironment in tumor tissue and contribute to tumor evasion from immune response. Specifically, some studies have indicated that Treg cell infiltration in malignant ascites and peripheral blood has been associated with poor clinical outcome. Methods: The number of CD4+, CD25+, forkhead box p3+ (Foxp3+) lymphocytes was assessed via flow cytometry in ascites and peripheral blood from 24 women with epithelial ovarian cancer (EOC). Overall survival was associated with Treg levels. Results: The study indicated an increase in the Treg cell subset from peripheral blood of EOC patients compared with those in healthy controls. Treg infiltration in ascites was higher than in blood into EOC patients. The patients with high infiltration of Treg in blood revealed less overall survival compared to a counterpart with normal levels of Treg. Regarding the association between patients with increased levels of Treg in ascites with overall survival there was no disadvantage found, compared to ascites from patients with normal levels of Treg. Conclusion: Study suggests that Treg lymphocytes were increased in ascites and peripheral blood in EOC patients and could be associated with diminished overall survival, via impairment antitumor immune response.