title: Evaluation of ecological and in vitro effects of boron on prostate cancer risk (United States).
abstract: OBJECTIVE
  To determine: (1) the correlation of prostate cancer incidence and mortality with groundwater boron and selenium concentrations; and (2) the impact of boron on prostate cancer cell proliferation during co-treatment with alternative chemo-preventative agents, along with boron pre-treatment effects on cell sensitivity to ionizing radiation.
  
  
  METHODS
  For regression analysis, data on prostate cancer incidence and mortality were obtained from the Texas Cancer Registry, while groundwater boron and selenium concentrations were derived from the Texas Water Development Board. Cultured DU-145 prostate cancer cells were used to assess the impact of boric acid on cell proliferation when applied in combination with selenomethionine and genistein, or preceding radiation exposure.
  
  
  RESULTS
  Groundwater boron levels correlated with a decrease in prostate cancer incidence (R = 0.6) and mortality (R = 0.6) in state planning regions, whereas selenium did not (R = 0.1; R = 0.2). Growth inhibition was greater during combined treatments of boric acid and selenomethionine, or boric acid and genistein, versus singular treatments. 8-day boric acid pre-exposure enhanced the toxicity of ionizing radiation treatment, while dose-dependently decreasing the expression of anti-apoptotic protein Bcl-2.
  
  
  CONCLUSIONS
  Increased groundwater boron concentrations, across the state of Texas, correlate with reduced risk of prostate cancer incidence and mortality. Also, boric acid improves the anti-proliferative effectiveness of chemo-preventative agents, selenomethionine and genistein, while enhancing ionizing radiation cell kill.
authors.affiliation: Department of Environmental Health Sciences, University of California, Los Angeles, CA 90095-1772, USA.
authors.forename: Wade T
authors.initials: WT
authors.lastname: Barranco
authors.forename: Paul F
authors.initials: PF
authors.lastname: Hudak
authors.forename: Curtis D
authors.initials: CD
authors.lastname: Eckhert
mesh_terms: D016588:Anticarcinogenic Agents / Q000494:pharmacology*; D001888:Boric Acids / Q000494:pharmacology*; D001895:Boron / Q000032:analysis*; D049109:Cell Proliferation / Q000187:drug effects; D004777:Environment; D019833:Genistein / Q000494:pharmacology; D006801:Humans; D008297:Male; D011471:Prostatic Neoplasms / Q000453:epidemiology* / Q000401:mortality*; D011839:Radiation, Ionizing; D012044:Regression Analysis; D012307:Risk Factors; D012645:Selenomethionine / Q000494:pharmacology; D013781:Texas / Q000453:epidemiology; D014407:Tumor Cells, Cultured; D014481:United States; D014867:Water / Q000737:chemistry
chemical_list: D016588:Anticarcinogenic Agents; D001888:Boric Acids; D014867:Water; D012645:Selenomethionine; D019833:Genistein; D001895:Boron; C032688:boric acid