CD28 and ovarian cancer: Data from clinical investigation of ovarian cancer-associated CD4+CD25+, CD4+CD25+Foxp3+, CD8+CD28−, and CD8+Foxp3+ Tregs and their postoperative alterations indicated that Tregs percentage continues to decline in postoperative period with remarkable correlation with the tumor burden, thus can be used as an important factor in monitoring the immunological status of ovarian cancer patients (Wu et al., 2017a) (Fig. 2).