Table I.

Effects of PEITC-NAC, I3C and MI, alone or in combination, on lung tumor induction by a mixture of NNK plus BaP in A/J mice^a

Group	Temporal sequence	Chemopreventive agent (dose, μmol/g diet)	No. of mice at termination	Mean body weight at termination	Lung tumors
					Tumor incidence (%)	Tumors per mouse (mean ± SD)	Reduction in tumor multiplicity (%)	Adjusted Pb
1	—	None	20	24.5 ± 1.8	100	13.0 ± 4.1
2	A	PEITC-NAC (5)	15	24.1 ± 2.2	100	8.2 ± 2.0	37	0.0051
3	A	I3C (5)	17	24.8 ± 1.6	100	8.4 ± 1.5	35	0.0051
4	A	MI (56)	17	25.2 ± 1.4	100	6.8 ± 1.7	48	0.0012
5	A	PEITC-NAC (5) + I3C (5)	15	24.0 ± 1.4	100	6.3 ± 2.2	51	0.0010
6	B	PEITC-NAC (5) + I3C (5)	17	24.2 ± 2.1	100	9.3 ± 2.7	29	0.0075
7	A	PEITC-NAC (5) + MI (56)	17	24.6 ± 1.8	100	4.9 ± 1.8	62	<0.0001
8	A	I3C (5) + MI (56)	17	23.9 ± 2.0	94.2	4.8 ± 1.9	63	<0.0001
9	B	I3C (5) + MI (56)	16	24.7 ± 1.6	100	6.2 ± 1.7	52	0.0006
10	A	PEITC-NAC (5) + I3C (5) + MI (56)	16	23.5 ± 1.4	100	3.6 ± 1.4	73	<0.0001
11	B	PEITC-NAC (5) + I3C (5) + MI (56)	16	23.8 ± 1.7	100	5.8 ± 2.4	55	<0.0001
12	—	None	10	26.6 ± 2.4	36.8	0.1 ± 0.3	—

^aBeginning at age 6–7 weeks, groups of female A/J mice received a mixture of NNK plus BaP (2 μmol of each) orally by gavage twice a week for 4 weeks (groups 1–11). PEITC-NAC, I3C and MI, alone or in combination, were added to the diet in two temporal sequences, either beginning at 50% carcinogen treatment (A) or 1 week post-carcinogen (B). The experiment was terminated 19 weeks after the last dose of carcinogen.

^bCompared with group 1.