Prostate Cancer Outcome and Tissue Levels of Metal Ions

BACKGROUND. There are several studies examining prostate cancer and exposure to cadmium, iron, selenium, and zinc. Less data are available on the possible influence of these metal ions on prostate cancer outcome. This study measured levels of these ions in prostatectomy samples in order to examine possible associations between metal concentrations and disease outcome. METHODS. We obtained formalin fixed paraffin embedded tissue blocks of prostatectomy samples of 40 patients with PSA recurrence, matched 1:1 (for year of surgery, race, age, Gleason grading, and pathology TNM classification) with tissue blocks from 40 patients without recurrence (n 80). Case-control pairs were compared for the levels of metals in areas adjacent to tumors. Inductively coupled plasma-mass spectrometry (ICP-MS) was used for quantification of Cd, Fe, Zn, and Se. RESULTS. Patients with biochemical (PSA) recurrence of disease had 12% lower median iron (95 mg/g vs. 111 mg/g; P 0.04) and 21% lower zinc (279 mg/g vs. 346 mg/g; P 0.04) concentrations in the normal-appearing tissue immediately adjacent to cancer areas. Differences incadmium (0.489 mg/g vs. 0.439 mg/g; 4% higher) and selenium (1.68 mg/g vs. 1.58 mg/g; 5% higher) levels were not statistically significant in recurrence cases, when compared to non-recurrences (P = 0.40 and 0.21, respectively). CONCLUSIONS. There is an association between low zinc and low iron prostate tissue levels and biochemical recurrence in prostate cancer. Whether these novel findings are a cause or effect of more aggressive tumors, or whether low zinc and iron prostatic levels raise implications for therapy, remains to be investigated. Prostate 71:1231-1238, 2011. (C) 2011 Wiley-Liss, Inc.