IGFBP4 and cancer: In addition, IGFBPs may play synergistic roles in various cancer-related pathways because a significant correlation was detected (Fig. 6C), such as IGFBP3-IGFBP4(r = 0.54), IGFBP4-IGFBP7(r = 0.50) and IGFBP5-IGFBP7(r = 0.49).