PIWIL1 and hepatocellular carcinoma: For instance, PIWIL1 overexpression has been reported to accelerate the growth of HCC tumors through increasing oxygen consumption and energy production via fatty acid metabolism; additionally, PIWIL1-overexpressing HCC cells can attach myeloid-derived suppressor cells (MDSCs) into the tumor microenvironment, which in turn initiate the expression of immunosuppressive cytokine IL10 [39].