CXCL12 and cancer: As chemotherapeutics induce damage in the tumour microenvironment, this results in a stress response in MSCs and cancer-associated fibroblasts, which secrete various growth and anti-apoptotic factors (e.g., IL-6, IL-7, IL-8, CXCL12, and VEGF) that promote cell survival, proliferation, invasion, and the metastasis of cancer cells [84,85,86,87,88,89,90,91].