Chemopreventive effects of phenethyl isothiocyanate on lung and pancreatic tumorigenesis in N-nitrosobis(2-oxopropyl)amine-treated hamsters.

The chemopreventive effects of phenethyl isothiocyanate (PEITC) were investigated in N-nitrosobis(2-oxopropyl)-amine (BOP)-treated hamsters. Female 5-week-old Syrian golden hamsters were divided into six groups. Animals in groups 1-3, each consisting of 30 hamsters, were given BOP by two subcutaneous injections 7 days apart at a dose of 20 mg/kg body weight, plus either 100, 10 or 0 micromol of PEITC in corn oil by gavage 2 h prior to each BOP treatment, respectively per group. Animals in groups 4 and 5, each consisting of 10 hamsters, were given 100 and 10 micromol of PEITC alone in corn oil, and 10 animals in group 6 served as a vehicle control. Animals were sacrificed 52 weeks after the first BOP injection. Both the incidences and multiplicities of lung adenomas and/or adenocarcinomas were significantly decreased in a dose-dependent manner by PEITC treatments (P < 0.01 or 0.05). The lung tumor incidences were inhibited by 100% with 100 micromol PEITC and by 82% with the 10 micromol dosage. In addition, the high dose of PEITC also significantly inhibited pancreatic carcinogenesis (P < 0.05) and showed a tendency to lower the incidences of liver and renal tumors, although these effects were not statistically significant. Under the present experimental conditions, PEITC itself did not cause any apparent toxicity. Our results thus indicate that PEITC is a remarkably effective chemopreventive agent for the BOP-induced lung and pancreatic tumors in hamsters.