['It has been well established that tumor-associated macrophages (TAMs) play a tumor promoting role in endometrial endometrioid adenocarcinoma (EEC). But the association with TAMs and sex hormone receptor expression, and progression of precancerous endometrial lesions in EEC has been little reported.', 'We used immunohistochemistry to examine the expression of CD68, CD34, vascular endothelial growth factor (VEGF), estrogen receptor (ER) and progesterone receptor (PR) in 95 cases of EEC, as well as 35 cases of endometrial hyperplasia (including 15 atypical hyperplasia, 10 complex hyperplasia and 10 simple hyperplasia). We also correlated TAMs count with various clinicopathological factors, sex hormone receptor, and prognostic value in patients with EEC.', 'We identified that TAMs count increased linearly with disease progression (mean count per case at × 200 magnification: simple hyperplasia, 6.30; complex hyperplasia, 11.20; atypical hyperplasia, 29.40; EEC 55.81, respectively; P < 0.001), that microvascular density (MVD) also increased accordingly (27.50, 30.20, 50.13 and 59.94, respectively; P < 0.001). The expression of progesterone receptor, not of estrogen receptor, significantly decreased with disease progression (P < 0.05). Moreover, histopathologic grades, International Federation of Gynecology and Obstetrics (FIGO) stage (2009), depth of myometrial invasion, pelvic lymph node metastasis, lymphovascular space invasion, and expression of PR and VEGF were associated with TAMs count (P = 0.0001, P = 0.004, P = 0.0001, P = 0.04, P = 0.0001, P = 0.0001, P = 0.0001, respectively). Progesterone receptor expression was also associated with histopathologic grades, lymphovascular space invasion, VEGF and high TAMs (P = 0.035, P = 0.022, P = 0.014, P = 0.001, respectively). The estimated 5-year survival rate of patients with low TAMs was significantly higher than those with high TAMs (96.4% vs 69.8%, P = 0.002).'] Do tumor-associated macrophages correlate with progesterone receptor loss in endometrial endometrioid adenocarcinoma?