The transfection of cancer cells with pcDNA3-MnSOD significantly enhanced the expression of MnSOD, fibronectin, vimentin, MMP-9, and N-cadherin, and decreased the levels of E-cadherin in colon cancer cells above the basal level, indicating the mesenchymal-phenotype of these cells is promoted by when MnSOD levels go high in the cell. The gene discussed is MMP9; the disease is cancer.