Table 1.

Summary of urethane-induced lung carcinogenesis experiments

A. Short-term observation (8 weeks) after single urethane administration in Nrf2+/+ and Nrf2−/− mice
Incidence of lung surface tumorsAverage number of lung surface tumors per mouse
Tumor size (mm)0.5 < ϕ
Nrf2+/+ (n = 10)5/10 (50.0%)0.8 ± 0.5 (n = 10)
Nrf2−/− (n = 9)9/9b (100.0%)3.1 ± 1.1a (n = 9)
B. Middle-term observation (16 weeks) after single urethane treatment in Nrf2+/+ and Nrf2−/− mice
Incidence of lung surface tumorsAverage number of lung surface tumors per mouse
Tumor size (mm)0.5 < ϕ1.5 < ϕ0.5 < ϕ1.5 < ϕ
Nrf2+/+ (n = 7)7/7 (100.0%)7/7 (100.0%)18.1 ± 13.34.7 ± 3.4
Nrf2−/− (n = 8)8/8 (100.0%)1/8a (12.5%)11.3 ± 7.00.125 ± 0.3a
C. Long-term observation (24 weeks) after four weekly contiguous urethane-treatment in Nrf2+/+ and Nrf2−/− mice
Incidence of lung surface tumorsNumber of lung surface tumors per mouse
Tumor size (mm)0.5 < ϕ < 2.02.0 < ϕ0.5 < ϕ2.0 < ϕ
Nrf2+/+ (n = 10)10/10 (100.0%)6/10a (60.0%)35.7 ± 22.5a4.9 ± 6.59a
Nrf2+/− (n = 5)5/5 (100.0%)2/5b (40.0%)37.0 ± 10.9a0.4 ± 0.55b
Nrf2−/− (n = 10)10/10 (100.0%)0/10 (0.0%)16.4 ± 12.60.0 ± 0.0
  • aP < 0.01 compared with wild-type mice.

  • bP < 0.05 compared with wild-type mice.