The expression levels of angiogenin, cluster of differentiation 105 (CD105), inter-cellular adhesion molecule 1 (ICAM-1), chemokine (C-X-C motif) ligand 10 (CXCL10), leptin, lipocalin-2, matrix metallopeptidase 9 (MMP-9), osteopontin, RBP4, plasminogen activator inhibitor-1 (PAI-1), α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor binding protein (ABP), CD31, thermal interface material 2 (TIM-2) and vascular cell adhesion molecule 1 (VCAM-1) were significantly higher in the endometriosis group compared with the control group (Figure 1B, P < 0.05, respectively). Here, MMP9 is linked to endometriosis.