MMP9 and central nervous system cancer: Further, western blot was used to detect the changes of the expression of VM formation-related proteins MMP2, MMP9, and VE-cadherin in glioma cells after HNRNPD knockdown, we found that compared with HNRNPD(−)-NC group, the expression of the proteins decreased significantly in HNRNPD(−) group (Fig. 1F).