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. Author manuscript; available in PMC: 2012 Feb 28.
Published in final edited form as: Clin Investig (Lond). 2011 Dec 1;1(12):1695–1706. doi: 10.4155/cli.11.150

Figure 2. A vicious cycle of tumor cell-induced resorption and resorption-induced tumor growth.

Figure 2

Tumor cells metastasize to the bone marrow where Src signaling mediates their growth and movement within the marrow cavity. The tumor cells secrete osteoclast-stimulating factors, including PTHrP, which stimulate osteoclast formation and activation by inducing expression of RANKL by osteoblastic stromal cells within the marrow. Osteoclasts resorb the bone, releasing growth factors, including TGF-β and FGFs, which stimulate tumor cell proliferation. TGF-β also induces expression of PTHrP by the tumor cells. Src regulates various functions of cancer cells and osteoclasts, and Src inhibition could reduce growth of metastatic cancer cells in bone by disrupting this vicious cycle.