HIF1A and hepatocellular carcinoma: First, CAFs directly promote tumour proliferation and metastasis by secreting growth factors (e.g., CXCL11, CCL5): CAF-derived CCL5 enhances HCC metastasis by triggering the HIF1α/ZEB1 axis, while CXCL11 directly promotes HCC cell proliferation [28, 29].