PTHLH and breast cancer: For example, the surface chemotactic factors on BC cells include CXC chemokine receptor (CXCR) (25), transforming growth factor-β (TGF-β) (10), insulin-like growth factor (IGF) (11), matrix metalloproteinases (MMPs) (26), parathyroid hormone related protein (PTHrP) (27), cancer-associated fibroblasts (CAFs) (28), BSP (29), IL-6 (30), hepcidin (31), periostin protein (32), OPN (29), MFAP5 (33), and RANKL (34, 35).