S100A9 and neoplasm: It is a calcium‐binding protein that was first identified as a proinflammatory mediator released by bone marrow‐derived cells in response to cell damage, infection, or inflammation.[9, 10] Recent studies have shown that S100A9 is also involved in carcinogenesis and tumor progression and inhibits the tumor immune response.[11, 12, 13] S100A9 is upregulated and correlated with poor differentiation in HCC.[14] S100A9 might activate the reactive oxygen species (ROS)‐dependent signaling pathways and protect against cell death.[15] However, its intrinsic mechanisms remain underexplored.