IGFBP3 (Insulin-Like Growth Factor Binding Protein 3) is a protein that binds to insulin-like growth factors (IGFs), regulating their availability and activity within the body. This control affects cell growth, development, and metabolism. IGFBP3 is extensively researched in cancer studies, as it can either inhibit or enhance IGF effects depending on the cellular environment, making it a crucial element in tumour growth and potential treatment strategies.