ACSL4 and hepatocellular carcinoma: ACSL4 (or FACL4) is a central enzyme controlling the unesterified arachidonic acid level in cells.19 The expression of ACSL4 was consistently shown to be upregulated in most of the HCC patient samples in our previously published expression data set11,12,20 and other published data sets, including TCGA (Supplementary Figure S6A) and GSE14520 (Supplementary Figure S6B), respectively.