Fibroblasts of cancer cells play an important role in this process.CXCR2 receptors on the surface of CAFs can bind to self-secreted CXCL1, and can also release IL-8, CCL7, IL-1β, etc., providing support for cancer cells; at the same time, CXCL12, CCL2, and TGF-β secreted by cancer cells play a supporting role, promoting the transformation of normal fibroblasts into CAFs. The gene discussed is CCL7; the disease is cancer.