STAT3 and keloid: However, it was recently suggested that MSC exosomes isolated from BM stimulate numerous signaling pathways, mainly STAT3 expression, which participates in its phosphorylation and in the formation of keloid fibroblasts and elevates the expression of growth factors that are mainly related to wound healing, such as IL-8 and C-X-C motif chemokine ligand 1 (CXCL1), nerve growth factor, HGF, IGF-1, and SDF-1 (Shabbir et al., 2015).