The present study shows for the first time that the combination of suppressive and pro-inflammatory immune markers, TNFR2-expressing Tregs and IL-6, found to be over-expressed in the peripheral blood of advanced high-grade serous ovarian cancer patients at diagnosis, are the most informative immune markers able to discriminate between those with ovarian cancers, benign ovarian masses and normal ovaries, and have superior predictive abilities compared to conventional tests and current biomarkers when used in combination. The gene discussed is IL6; the disease is ovarian cancer.