Immunohistochemistry 56 biopsy samples of 28 patients were used for immunohistochemical analysis. For LIF, integrin αv, VEGF and MMP-9 studies 4 um paraffin-embedded sections were deparaffinized 20 min in acetone at 70℃. Endogenous peroxidase was blocked with 3% H2O2 for 10 min. Antigen retrieval was boiling by heating for 5 min in 0.01 M citrate buffer at pH 6.0,and then the sections were incubated overnight at 4℃ with the specific antibodies which were diluted at 1:50. The antibodies used in this study were polyclonal antibodies (PAB) LIF, integrin αv, VEGF and MMP-9 (BA 1239, BA0957,BA0407 and BA0573, Booster Co Ltd, Wuhan, China). The sections were rinsed in phosphate-buffered saline (PBS), blocked with 10% normal goat serum for 30 min and then incubated with goat anti-rabbit biotinylated immunoglobulins (IgG)(SV0002, Booster Co Ltd, Wuhan, China) at 37℃ for 30 min. For integrin β3 study, the sections were incubated with 3% hydrogen peroxide for 10 min after hot repair of antigen by boiling at 95℃ of 0.01M citrate buffer(pH6.0), then incubated with polyclonal antibodies integrin β3 (sc-6626, santa, USA) diluted at 1:100 overnight at 4℃. Polymer Helper (PV-9003, Zhong-Shang Co Ltd, Beijing, China) was added at room temperature and with a interval of 20 min, Poly Peroxidase-anti-goat IgG (PV-9003, Zhong-Shang Co Ltd, Beijing, China) was added. The slides were then washed in PBS and colored by 3,3-diaminobenzidine in H2O2 (DAB, vitrogen, California, USA). The sections were finally washed in water. In every case a negative control was performed by omission of incubation with the primary specific antibody. The reactivity of each polyclonal antibody with endometrial glands and surface epithelium, stromal cells was assessed. Staining was evaluated semiquantitatively by using a grading system. Staining intensity and the number of stained cells were graded on a scale of 0=no staining, +/- = few stained cells, + = faint staining, ++ = moderate staining, and +++ = strong staining. The formula of H-score=ΣPi(i+1) was used to calculation. One observer who was blinded to identify of the slides performed all the assessments. After completion of the study, the same observer reexamined the slides to ensure reproducibility of the semiquantitative assessment.