Table 1.

Effect of Polyphenon E on OH-BBN–induced urinary bladder cancers

GroupCarcinogen*TreatmentLarge cancersPercent of rats with microscopic lesions (%)§
1OH-BBNPolyphenon E, 250 mg/kg BW/d6/34 (18%)100
2OH-BBNPolyphenon E, 100 mg/kg BW/d14/35 (40%)100
3OH-BBNNone20/34 (59%)100
  • * OH-BBN was administered to rats twice per week for 8 wks beginning when the animals were 56 d of age (n = 30 rats per group).

  • Chemopreventive agents were administered beginning 1 wk after the final OH-BBN treatment.

  • The study was terminated 7 mo after the final OH-BBN treatment. Large cancers were those that were >5 mm in diameter and filled >50% of the urinary bladder lumen.

  • § Percentage of rats with microscopic lesions (hyperplasia, papilloma, cancer).

  • Significantly different from group 4 (P < 0.05).