HGF and neoplasm: Since extensive ECM remodeling is a necessary step for tumor cell invasion, it is not surprising that the same signaling pathways we have mentioned throughout this review (WNT, PI3K, MAPK, HGF/c-MET, TGF-β) have also been found to significantly upregulate the expression of a myriad of proteolytic enzymes in malignant glioma [46, 66, 133, 244–247].