Insulin-like growth factor-binding protein 1 (IGFBP-1), also known as placental protein 12 (PP12), is a protein encoded by the IGFBP1 gene. It binds insulin-like growth factors (IGFs) I and II and circulates in plasma. Such binding prolongs the half-life of IGFs and alters their interaction with cell surface receptors.IGFBPs regulate the biological activity of IGF proteins.Post-transcriptional modifications of IGFBP (e.g., glycosylation, phosphorylation, and protein hydrolysis) alter the affinity of the bound protein for IGFs. High levels of IGFBP-1 may be a marker of catabolic status, and studies have shown that women with high levels of IGFBP-1 have less muscle mass. Higher serum IGFBP-1/IGF-1 ratios in patients with nasopharyngeal carcinoma are significantly associated with poorer prognosis. Local IGFBP1 levels have been reported to have an effect on coronary plaque formation.