The possible mechanisms of action of PIWIL1 promoting the tumor progression might be as follows [23–27]: (1) PIWIL1 and the cell proliferation marker Ki-67 had similar expression patterns in the gastric cancer cells, and interference by PIWIL1 RNA could cause cell cycle arrest at the G2/M stage in gastric cancer cells. The gene discussed is PIWIL1; the disease is neoplasm.