COL4A1 and cancer: More importantly, fibroblasts educated by exosomes from high-metastatic cancer cells expressed higher level of pro-inflammatory genes, such as IL-1β, IL-6, IL-8, TGF-β, CXCL12, Collagen type I (COL1A1), Collagen type III (COL3A1), and Collagen type IV (COL4A1), which have important roles in modulating the inflammation microenvironment and promoting carcinoma development (Fig. 1f).