CXCL12 and neoplasm: These factors include chemokines, cytokines and growth factors, such as the vascular endothelial growth factor (VEGF), CXCL12 and CXCL14, and interleukins (ILs) IL-6 and IL-17A, which are critical for tumour cell proliferation, angiogenesis, invasion, inflammation, metastasis and drug resistance [9].