Two-year intermittent exposure of a multiwalled carbon nanotube by intratracheal instillation induces lung tumors and pleural mesotheliomas in F344 rats

Table 3 Incidence of lung tumors and malignant pleural mesothelioma

	Control	Low-dose	High-dose
Number of rats examined	30	29	28
Lung
Bronchiolo-alveolar adenocarcinoma (%)	1 (3.3)	2 (6.9)	6* (21.4)
Bronchiolo-alveolar adenoma (%)	0 (0)	1 (3.5)	4* (14.3)
Non-keratinizing epithelioma (%)	0 (0)	0 (0)	1 (3.6)
Total tumors (%)	1 (3.3)	3 (10.3)	11* (39.3)
Pleura
Malignant pleural mesothelioma (%)	0	4 (13.8)	12* (42.9)

Values show the number of animals bearing the tumor
Values in parentheses are the percentage of tumor incidences; 100 × number of animals with tumor ÷ number of animals examined
*Significantly different from Control (by Fisher's exact test)

ISSN: 1743-8977