MMP9 and cancer: In summary, this study points at the existence of a ‘vicious cycle’ (Fig. 6) whereby gal-8 secreted both by tumor and naïve cells present in the tumor microenvironment, promotes in an autocrine and paracrine manner the secretion of chemokines, cytokines, and additional proteins (e.g. MMP9, GAS6) that support tumor growth and induce recruitment of cancer cells to the metastatic niche.