The WFA-staining intensity was evaluated separately for the epithelial component and the stromal component and stratified as follows: 0 (negative), 1 (weak), 2 (moderate), and 3 (strong). Two gynecologists (K. K. and M. Y.) scored all samples independently, and discrepancies were resolved by simultaneous examination. *p < 0.05 vs. eutopic endometrium (Student’s t-test).