CAFs can effectively promote angiogenesis in tumor tissues by secreting a variety of pro-angiogenic factors such as vascular endothelial growth factor, fibroblast growth factor, and IL-6, and can also recruit endothelial progenitor cells into tumor tissues through stromal-derived factor-1 (SDF-1) to promote angiogenesis (47). This evidence concerns the gene IL6 and neoplasm.