Differential distribution of tumor-associated macrophages and Treg/Th17 cells in the progression of malignant and benign epithelial ovarian tumors

Epithelial ovarian cancer (EOC) is one of the predominant causes of cancer-associated mortality in women with gynecological oncology. Tumor-associated macrophages (TAMs), regulatory T cells (Treg cells) and T helper cell 17 (Th17) cells have been hypothesized to be involved in the progression of EOC. However, the association between TAMs and T cells remains to be elucidated. The aim of the present study was to investigate the differential distribution of TAMs, Treg cells and Th17 cells in benign ovarian tumor tissues and in tissues from patients with EOC, and to examine their association with the clinical pathology of EOC. A total of 126 tissue samples from patients with EOC and 26 tissue samples from patients with benign ovarian tumors were analyzed, and it was identified that the distribution of TAMs, Treg cells, Th17 cells and the ratio of Treg/Th17 cells were higher in the patients with EOC using triple color immunofluorescence confocal microscopy. The high frequency of TAMs and ratio of Treg/Th17 cells in late tumor grades suggested that they may be significant in tumor progression. The frequency of TAMs was different between the histological types of EOC. Immunohistochemistry was used to investigate the microvessel density (MVD) in the EOC and benign ovarian tumor tissues. A higher MVD was observed in the EOC patient tissues, particularly, in the late tumor grade tissues. The present study provided clinical data demonstrating the high distribution of TAMs and T-cells in EOC, which may contribute to tumor progression through angiogenesis. The mechanisms by which TAMs are associated with Treg cells and Th17 cells requires further investigation as prognostic factors and therapeutic targets for EOC.