HIF1A and hepatocellular carcinoma: Mechanistically, we found that CAF-derived CCL5 inhibited the ubiquitination and degradation of hypoxia-inducible factor 1 alpha (HIF1α) by binding to specific receptors, maintained HIF1α under normoxia, thereby up-regulated the downstream gene zinc finger enhancer-binding protein 1 (ZEB1) and induced epithelial-mesenchymal transition (EMT), ultimately validating its ability to promote lung metastasis of HCC.