Expression of MMP-9, VEGFR-2, VCAM-1, and eNOS in tissue samples from patients with cAVM in mRNA levels. (a) The representative mRNA levels of MMP-9, VEGFR-2, VCAM-1, and eNOS in tissue samples from twenty patients with CAVM and twenty controls. (b) The relative mRNA level of MMP-9, VEGFR-2, VCAM-1, and eNOS. β-actin was used as a reference gene. mRNA expression was quantified using the 2−ΔΔCT method, and t-tests were used for statistical analysis. The four mRNAs (MMP-9, VCAM-1, VEGFR-2, and eNOS) were validated in twenty group samples (one control sample and one cAVM sample per group) by real-time quantitative PCR, and similar trends were observed in each group. Three of the twenty validated groups are shown. MMP-9: Matrix metalloproteinase-9; VEGFR-2: Vascular endothelial growth factor receptor-2; VCAM-1: Vascular cell adhesion molecule-1; eNOS: Endothelial nitric oxide synthase; PCR: Polymerase chain reaction.