CXCL12 and neoplasm: CAFs secrete cytokines such as TGF-β, IL-6, and CXCL12, which enhance CSC proliferation, maintain stemness, drive EMT, and facilitate tumor invasion and metastasis.278 CAFs also contribute to therapeutic resistance by producing glutathione and ROS-scavenging molecules, shielding CSCs from chemotherapy-induced oxidative damage.242