Collectively, miR-18a treatment promoted induction of M1 macrophages (F4/80+IFNγ+ and F4/80+IL-12+) with upregulated co-stimulatory factors such as CD80, and iNOS while inhibiting M2 macrophages (F4/80+TGFβ+, F4/80+IL-10+) in the liver of metastatic colon tumor bearing mice. Here, NOS2 is linked to metastatic malignant neoplasm in the colon.