The aim of this study was to investigate the expression of macrophage migration inhibitory factor (MMIF),hypoxia-inducible factor-1 α (HIF-1 αt) and vascular endothelial growth factor (VEGF) in the serum and endometrial tissues of patients with endometriosis (EM) and the clinical significance.Eighty EM patients [American Reproductive Association stage I (n=20),stage Ⅱ (n=22),stage Ⅲ (n=21) and stage Ⅳ (n=17)] were enrolled and divided into mild (10-14 points,n=28),moderate (16-24 points,n=27) and severe (26-30 points,n=25) dysmenorrhea groups.The control group included 40 healthy women of childbearing age who underwent routine healthcare examinations in the enrolment period.The expression of MMIF,HIF-1α and VEGF in the serum and endometrial tissues was measured by enzyme-linked immunosorbent assay and West blotting,respectively.Meanwhile,the sensitivity and specificity of serum MMIF,HIF-1α,and VEGF when separately used as single indexes or jointly used as one index were examined as well.The results showed that serum concentrations of MMIF,HIF-1α,and VEGF were significantly higher in EM patients than in controls (P＜0.05).The expression of all three proteins in both serum and endometrial tissues increased significantly with the R-AFS stage (P＜0.05) and with dysmenorrheal severity (P＜0.05).The sensitivity and specificity of the combined detection of serum MMIF,HIF-1α,and VEGF levels were significantly higher than those of single index detection (P＜0.05).In conclusion,the expression of MMIF,HIF-1α,and VEGF in the serum and endometrial tissues may be used to assess the stage of EM and the severity of dysmenorrhea.Combined evaluation of MMIF,HIF-1α,and VEGF significantly improves the diagnostic sensitivity and specificity.