Due to the lowest PPFIA4 expression in SW403 cells and the highest PPFIA4 expression among all colon cancer cell lines investigated in our study, we proceeded to overexpress PPFIA4 (ov-PPFIA4) in SW403 cells by transfecting PPFIA4 expression plasmid, as well as knocking down PPFIA4 using shRNAs in HCT116 cells. The gene discussed is PPFIA4; the disease is malignant colon neoplasm.