IL6 and cancer: TGF-β increases the expression of PTHrP and other growth factors like IL-1, IL-6, IL-8, IL-11, prostaglandin E-2 (PGE2), macrophage colony stimulating factor (M-CSF), and tumor necrosis factor α (TNF-α) by direct impact on cancer cells, resulting in enhanced tumor growth in BM [7, 15].