Enhanced expression of vascular endothelial growth factor and increased microvascular density in women with endometrial hyperplasia: a possible relationship with uterine natural killer cells

This case-control study aimed to investigate the expression of natural killer cells (NKCs) and the integrated optical density (IOD) of vascular endothelial growth factor (VEGF) and to quantify microvascular density (MVD) in endometrial biopsies from women with endometrial hyperplasia (EH) relative to normal subjects. Histological data from four groups were analyzed. The study population included 30 women with simple EH without atypia, 25 patients with complex EH without atypia, 25 with complex EH with atypia and 25 healthy women with non-hyperplastic endometrium (control group). Paraffin sections were immunostained with antibodies against CD56, VEGF-A and CD34 using an Avidin-Biotin-Peroxidase technique. The evaluation of NKC density and IOD of VEGF expression and measurement of MVD were performed using light microscopy examination and image analysis techniques. Increased numbers of NKCs were documented in cases of complex EH with atypia compared with the other groups (p