S100A9 and hepatocellular carcinoma: PGAM5, a serine/threonine phosphatase that has no apparent phosphoglycerate mutase activity but displays phosphoserine/threonine phosphatase activity, has recently been shown to play important roles in a variety of cellular processes, including the regulation of mitochondrial function and the mediation of immune signaling.[35, 36, 37] We illustrated the tumor‐promoting function of PGAM5 in HCC and identified PGAM5 as the functional downstream target of S100A9.