IGF1R and breast cancer: Thus, IGF1, modulated by IGF-binding protein-3 (IGFBP-3), and IGF1R were associated with stimulation of the pro-growth MAPK signal transduction pathway and the PI3K/Akt anti-apoptotic pathway that sustains BC development [62,65], so up to 50% of BC cases express the activated form of IGF1R [66].