Figure 1.

Schematic representation of the IGF-1 signaling on promoting PCa development in tumor niche. Autocrine and paracrine IGF-1 signaling from the malignant cells, fibroblast, and ECM can contribute to tumor growth and distant metastasis in PCa. IGF-1 can induce by regulating the mutation of oncogenes and tumor suppressor genes. It can induce angiogenesis in the tumor microenvironment by enhancing VEGF expression and promoting degradation of ECM components by stimulating MMP release to favor metastasis of cancer cells. In addition, IGF-1 produced by the bone matrix can increase the collagenolytic and osteoblast activity of neoplastic cells, thus contributing to bone metastasis formation.