IGFBP3 and Familial prostate cancer: The largest pooled analysis, including our previous study, investigating the association between circulating concentrations of IGFs (IGF‐I, IGF‐II, IGFBP‐1, IGFBP‐2, and IGFBP‐3) and prostate cancer risk, provided strong evidence that IGF‐I is highly likely to be involved in prostate cancer development.47