Tumor cells prevent the differentiation of monocytes to macrophages, remaining in an immature state that contributes to create an immunotolerant environment: through the production of TGF-β, they can suppress the proliferation of T lymphocytes and induce Tregs, as well as expanding neoangiogenesis via the production of VEGF and MMP9 [39,42]. Here, MMP9 is linked to neoplasm.