IGFBP3 and Familial prostate cancer: In the case of human prostate cancer cell lines (PC3 and LNCaP), 24‐hrs treatment with IGF1 and insulin reduced (or tended to reduce) the expression of IGF1R, INSR and GHR (Fig. 4B, left panels), whereas only insulin increased the expression levels of Igfbp3 in LNCaP cells (Fig. 4B, right panel).