As PMN-MDSCs are naturally present in HCC tumors formed by wild type cells, regardless of PIWIL1 expression, which may also possess tumor-promoting effect, the complete removal of PMN-MDSCs by the injection of anti-Ly6G antibody in HCC tumors formed by wild type cells can also lead to tumor shrinkage. This evidence concerns the gene PIWIL1 and hepatocellular carcinoma.