Table 2

Effect of PBITa on postinitiation events of NMBA-induced tumorigenesis in the rat esophagus at 25 weeks

GroupNMBADietNo. of ratsTumor incidence (%)Tumor multiplicity mean ± SETumor volume (mm3)b mean ± SE
1-AIN-76A10000
2-50 ppm PBIT15000
3-100 ppm PBIT15000
4+AIN-76A2896.43.64 ± 0.425.68 ± 0.86
5+50 ppm PBIT2982.81.79 ± 0.25c4.97 ± 0.89
6+100 ppm PBIT3076.7d1.50 ± 0.24e4.57 ± 0.77
  • a PBIT, S,S′-1,4-phenylene-bis(1,2-ethanediyl)bis-isothiourea; NMBA, N-nitrosomethylbenzylamine.

  • b Tumor volume calculated as length × width × depth × π/6 assuming a prolate spheroid shape.

  • c Significantly lower than group 5 as determined by ANOVA (P < 0.001).

  • d Significantly lower than group 5 as determined by χ 2 test (P < 0.05).

  • e Significantly lower than group 5 as determined by ANOVA (P < 0.0001).