IL4 and breast cancer: Upon activation, these CAFs interact with the neighboring tumor cells continuously, which leads to breast cancer progression by releasing growth factors such as fibroblast growth factor 2 (FGF 2), insulin-like growth factor (IGF), CXCL12 or stromal-derived growth factor (SDF-1), EGF, TNF, VEGF2, as well as cytokines and chemokines such as CCL8, CXCL16, IL-4, IL-6, IL-8, CXCL1, and CXCL3, which increase breast cancer cells’ motility [143].