In our present study using a CCK-8 assay, we showed that knockdown of MTH1˴MTH2˴MTH3 or NUDT5 in SW480 and COLO320 cells reduced the rates of cell proliferation, implicating that MutT-related proteins at large play roles in CRC cell proliferation. The gene discussed is NUDT5; the disease is colorectal carcinoma.