Low serum insulin-like growth factor 1 (IGF-1): a significant association with prostate cancer.

Purpose: Insulin-like growth factor 1 (IGF-1) is an important mitogenic and antiapoptotic peptide that affects the proliferation of normal and malignant cells. Contradictory reports on the association between serum IGF-1 level and prostate cancer have been highlighted in the recent literature. The purpose of this study was to investigate the relation between serum levels of IGF-1 and prostate cancer.

Materials and methods: We analyzed a population of 57 patients who underwent radical prostatectomy (RP) for adenocarcinoma. Serum samples were collected before RP (T0), 6 months after RP (T6), and from 39 age-matched controls. IGF-1 levels were determined by the active IGF-1 Elisa kit (Diagnostic Systems Laboratories, Inc.). Parallel samples were evaluated for prostate-specific antigen (PSA) levels. Data between groups were analyzed using Welch's t-test and levels before RP and after 6 months were compared by paired t-test.

Results: The normal mean serum IGF-1 for case patients at T0 (124.6+/-58.2 ng/mL) was significantly lower than the control subjects (157.5+/-70.8 ng/mL; p = .0192). The normal mean serum IGF-1 for case patients at T0 (124.91+/-58.6 ng/mL) also was significantly lower when it was compared with the T6 group (148.49+/-57.2 ng/mL; p = .0056). No association was found between IGF-1 and PSA blood levels, or IGF-1 and patient weight (p = 0.2434). An inverse relation between IGF-1 levels and age in the normal controls (p = .0041) was observed.

Conclusion: Findings of this study indicate a significant association between low serum levels of IGF-1 and prostate cancer.