Although this result cannot directly conclude that p38 MAPK but not JNK was responsible for the IL10 production by MDSCs from PIWIL1-overexpressing HCC tumors, as a previous study found that both p38 MAPK and JNK inhibition can lead to downregulation of IL10,44 the observation that SB203580 has more potent inhibition than SP600125 on the IL10 production may suggest that p38 MAPK plays a more important role in mediating IL10 production by MDSCs of PIWIL1-overexpressing HCC tumors. This evidence concerns the gene PIWIL1 and hepatocellular carcinoma.