During the initial stages of osteosarcoma invasion, growth factors such as TGF-β are released from the degraded bone matrix and act on osteosarcoma cells, stimulating the release of PTHrP, interleukin-6 (IL-6) and interleukin-11 (IL-11) [114, 115]. The gene discussed is TGFB1; the disease is osteosarcoma.