AKT1 and thyroid gland carcinoma: As expected, overexpression of IGFBP7 markedly reduced the phosphorylation of AKT (Ser473 and Thr308) in various thyroid cancer cells, whereas silencing of IGFBP7 enhanced AKT phosphorylation (Ser473 and Thr308) (Fig. 5a), indicating that IGFBP7 suppresses phosphorylation-mediated activation of AKT.