Complications also arise from the fact that HGF/MET are highly expressed in GBM with expression correlating with grade [11]; indeed, this is compounded by co-expression of a HGF activator, a serine proteinase referred to as HGF activator (HGFA) [32], reinforcing an autocrine loop in highly malignant GBM [33]. This evidence concerns the gene HGFAC and glioblastoma.