A nested case-control study in the prospective prostate cancer screening trial was conducted to examine the associations between IGF1/IGFBP3 levels and the risk of prostate cancer, in this trial, a total of 727 incident prostate cancer cases and 887 matched controls were selected for analyses, the result indicated that the bioavailability of IGF1 was associated with risk for aggressive prostate cancer in obese men (Weiss et al., 2007). This evidence concerns the gene IGF1 and prostate cancer.