Carcinogenic effect of potassium octatitanate (POT) fibers in the lung and pleura of male Fischer 344 rats after intrapulmonary administration

Table 1 Proliferative lesions in the lung and pleura

Group	Untreated	Vehicle	r-nTiO₂ 0.25 mg	r-nTiO₂ 0.50 mg	POT 0.25 mg	POT 0.50 mg	MWCNT-7 0.50 mg
Number of animals	19	19	20	19	17	16	14
Bronchiolo-alveolar hyperplasia	2	2	0	2	7	10**	14^a,***
Bronchiolo-alveolar adenoma	0	1	2	0	1	0	1
Bronchiolo-alveolar adenocarcinoma	3	0	0	2	0	2	5
Squamous cell carcinoma	0	0	0	0	1	0	0
Mesothelial cell hyperplasia	0	0	0	0	4*	7**	10***
Visceral mesothelioma	0	0	0	0	1	0	0
Parietal mesothelioma	0	0	0	0	2	1	2
Carcinoma + Mesothelioma	3	0	0	2	4	2^b	6^b

^aThree animals also had bronchiolar hyperplasia
^bOne animal had bronchiolo-alveolar carcinoma and parietal mesothelioma
*^,**^,***Different from both the Untreated and the Vehicle Control at p < 0.05, p < 0.01, p < 0.001, respectively

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