Table 1. Incidence of neoplastic changes in resH2 mice following injection with a CNT, carbon black, solvent, or MNU test substance.

		control	carbon black	CNT	MNU
Organ	Diagnosis/total number	10	10	10	10
Skin (back area)	Papilloma	0	0	0	2
	Keratoacanthoma	0	0	0	0
Skin (face)	Papilloma	0	0	0	3
	Keratoacanthoma	0	0	0	0
Skin (thigh)	Papilloma	0	0	0	1
	Keratoacanthoma	0	0	0	0
Spleen	Inflammatory pseudotumor	0	0	1	0
	Hemangioma	0	1	0	0
Hematopoietic system	Malignant lymphoma	0	0	0	2
	Epithelial thymoma	0	0	0	0
Kidneys	Hemangioma	0	0	0	0
Pancreas	Hemangioma	0	0	0	0
Lungs	Adenocarcinoma	0	0	0	0
	Adenoma	0	1	0	1
	Hemangioma	0	0	0	0
Forestomach	Papilloma	0	0	0	10*
	Basal cell tumor	0	0	0	0
	Squamous cell carcinoma	0	0	0	0
Perineal	Papilloma	0	0	0	5**

*,**: significant differences at p = 0.0000054125 and p = 0.016254, respectively (Fisher's direct method).