MMP9 and gastric cancer: In gastric cancer cells, HGF activates PI3K/AKT signaling leading to NF-κB activation and expression of Lipocalin 2 (a transporter of a small lipophilic ligand, which forms a heterodimer with MMP-9 in several cancer types), MMP-9 and heparanase (a sheddase of associated cytokines in several types of tumors), which finally promotes cell migration and invasion [96,97].