The long-chain fatty acids in a hypoxia-responsive gene SLC27A2-deficient hepatocellular carcinoma (HCC) were taken up by tumor-associated macrophages (TAMs), activating PPAR-γ transcriptional activity and promoting the enrichment of SPP1+ TAMs in hepatocellular carcinoma (49). Here, SPP1 is linked to hepatocellular carcinoma.