Aims of this study were to investigate (i) IR isoform composition and IGF-1 receptor expression and (ii) IRS balance in prostate cancer compared to benign tissue as well as to tumor adjacent benign tissue; and (iii) to bring these results in relation to p27Kip1, a well described cell cycle inhibitor in prostate cancer [17]. The gene discussed is IARS1; the disease is Familial prostate cancer.