Interestingly, CAFs could secrete exosomes encapsulating with miR-221/222 [89], miR-21, -378e, -143 [90] to enhance the development of cancer cells to a more aggressive phenotype with increased stemness, EMT ability, etc. Additionally, exosomes from interleukin-4 (IL-4) activated TAMs, upregulated the expression of miR-223 in breast cancer cells with co-culture systems, which further promoted the invasiveness of cancer cells by disrupting the Mef2c-β-catenin pathway [91]. The gene discussed is IL4; the disease is breast carcinoma.