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.

ABSTRACT

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-1tPSA and IGFBP-3tPSA 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.