The correlation between zinc and insulin-like growth factor 1 (IGF-1), its binding protein (IGFBP-3) and prostate-specific antigen (PSA) in prostate cancer

Background: The objective of the present study is to explore the association between zinc concentrations and insulin-like growth factor 1 (IGF-1), its binding protein (IGFBP-3) and total prostate-specific antigen (tPSA) levels in the serum of patients with prostate cancer (PCa) and prostate intraepithelial neoplasia (PIN), a pre-cancer state matched for age. Methods: The study was carried out in a group of 229 patients who had transurethral prostate biopsy performed. The patients were divided into three groups: control group (BPH), PIN group or PCa group. The patients had plasma zinc concentration determined by atomic absorption spectrometry; IGF-1, IGFBP-3 analyzed using the chemiluminescence method and tPSA detected in serum with DELFIA assay. Results: The studies revealed that, in PCa and PIN patients aged under 65 years, mean zinc concentrations were significantly lower compared with the control group. IGF-1 level significantly increased with decreasing level of zinc in plasma, hence a significantly decreased Zn/IGF-1 ratio. The mean tPSA concentration was significantly increased only in PCa patients of both age groups, whereas the Zn/tPSA ratio significantly decreased with increasing severity of neoplastic lesions, particularly in patients aged under 65 years. Statistical significance was noted for IGF-1: tPSA and IGFBP-3: tPSA ratios, being almost two-fold lower in the PCa patients than in the control group. Conclusions: A significantly lowered Zn/tPSA ratio appears to be a sensitive marker of neoplastic lesions, PCa and PIN, regardless of age. In men under 65 years, the Zn/IGF-1 ratio was reduced, depending on the stage of neoplastic lesions (PIN > PCa). These finding can be useful in early diagnosis of prostate cancer.