Insulin-like growth factor pathway-targeted therapy in breast cancer

The insulin-like growth factor (IGF) pathway plays an important role in cancer development, survival, metastasis, and resistance to antineoplastic therapies in various malignancies. Components of the IGF pathway are potential targets for novel anticancer therapy. In breast cancer, preclinical and clinical data suggest that IGF signaling is critical for tumor growth and resistance to therapy, leading to poor prognosis. There is also evidence of cross-talk between IGF, estrogen, erbB, and mTOR pathways; a potential mechanism of cancer resistance to hormonal or HER2-targeted therapy. This review discusses the rationale and strategies being evaluated in the clinical development of targeting the IGF pathway. It highlights the potential interactions between the IGF pathway and other therapies in breast cancer, and also focuses on the completed and ongoing clinical trials of different IGF pathway-targeted therapies in breast cancer.