Table 4.

Histopathological analysis of tumors in A/J mice receiving NNK with or without nicotine^a

Group	Treatment	Incidence (percent of mice)			Multiplicity (Average per Mouse ± SD)
		Adenoma	Adenoma with dysplasia	Carcinoma	Adenoma	Adenoma with dysplasia	Carcinoma
1 (n=14)	No nicotine/saline	7	7	0	0.07 ± 0.27	0.07 ± 0.27	0.0
2 (n = 15)	Nicotine 0–46 weeks/saline	8	0	15	0.08 ± 0.28	0.0	0.15 ± 0.40
3 (n= 18)	No nicotine/NNK	83	56	28	3.4 ± 2.4	0.83 ± 0.92	0.44 ± 0.78
4 (n = 18)	Nicotine 0–46 weeks/NNK	89	61	44	4.4 ± 2.7	1.0 ± 1.1	0.67 ± 0.91
5 (n = 19)	Nicotine 0–2 weeks/NNK	95	63	28	4.8 ± 3.5	1.0 ± 0.94	0.37 ± 0.68
6 (n = 20)	Nicotine 2–46 weeks/NNK	85	65	50	4.4 ± 2.6	0.8 ± 0.70	0.70 ± 0.80

^aTreatments were as described in Fig. 1 and Table 3. Histological analysis was not carried out on lungs from 5 mice in Groups 1 and 2. Premature deaths occurred in Groups 2–5 as follows: Group 2, one death, week 3, cause of death – unknown, no microscopic analysis of tissues; Group 3, one death week 5 cause of death – unknown and one death at week 29 cause of death – disseminated lymphoma, pulmonary adenomas present; Group 4, one death week 43 cause of death – respiratory distress, adenocarcinoma with multifocal pulmonary adenomas, bronchiolar epithelial hyperplasia, alveolar histiocytosis and hemorrhage and one death at week 37 after NNK injection. Cause of death – dorsal skin tumor (a large non-malignant hematoma) pulmonary adenomas present; Group 5, one death at week 11 euthanized due to “labored breathing” no microscopic analysis of tissues.