PIWIL1 and cancer: Cancer cells require a large amount of energy in a short period to proliferate rapidly.24 To suppose this, cancer cells were usually accelerating glucose uptake and utilizing anaerobic glycolysis to generate more energy in supporting the demands of rapid tumor progression.25 Interestingly, overexpression of PIWIL1 in HCC cells resulted in a significant increase of intracellular ATP, suggesting that PIWIL1 may promote energy production to support rapid cell proliferation (Fig. 2a).