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Target Organs and Levels of Evidence for TR-516

Toxicology and Carcinogenesis Studies of 2-Methylimidazole (CASRN 693-98-1) in F344/N Rats and B6C3F1 Mice (Feed Studies)

Chemical (Study Title) CASRN	Peer Review Date	Route/Exposure Levels	Study Laboratory
2-Methylimidazole 693-98-1	05/22/2003	Dosed-Feed MR: 0, 300, 1000, OR 3000 PPM; FR: 0, 1000, 2500, OR 5000 PPM; M: 0, 625, 1250, OR 2500 PPM; 60/SEX/SPECIES/GROUP	Southern Research Institute

Levels of Evidence

Male Rats: Some Evidence

Type	Organ/Tissue (Lesion)
Neoplastic Lesions	Thyroid Gland Follicular Cell: ADENOMA OR CARCINOMA 1/48 2/46 1/43 5/50
May Have Been Related	Liver: ADENOMA OR CARCINOMA 0/50 1/50 3/50 3/50
Non-Neoplastic Lesions	THYROID GLAND: FOLLICULAR CELL HYPERPLASIA LIVER: MIXED CELL FOCUS

Female Rats: Clear Evidence

Type	Organ/Tissue (Lesion)
Neoplastic Lesions	Thyroid Gland Follicular Cell: ADENOMA 0/49 0/48 0/42 5/48 CARCINOMA 1/49 1/48 1/42 7/48 COMBINED 1/49 1/48 1/42 11/48
May Have Been Related	Liver: ADENOMA 1/50 0/49 2/50 4/50
Non-Neoplastic Lesions	THYROID GLAND: FOLLICULAR CELL HYPERPLASIA; MINERALIZATION LIVER: BILE DUCT HYPERPLASIA; GRANULOMATOUS INFLAMMATION; MIXED CELL FOCUS SPLEEN: GRANULOMATOUS INFLAMMATION

Male Mice: Some Evidence

Type	Organ/Tissue (Lesion)
Neoplastic Lesions	Thyroid Gland Follicular Cell: ADENOMA 0/50 1/50 0/50 7/50 Liver: ADENOMA 7/50 14/50 13/50 18/50 CARCINOMA 4/50 8/50 14/50 6/50 COMBINED 10/50 22/50 22/50 22/50
Non-Neoplastic Lesions	THYROID GLAND: FOLLICULAR CELL HYPERPLASIA; FOLLICULAR CELL HYPERTROPHY LIVER: HEPATOCYTE CYTOPLASMIC ALTERATION; HEPATOCYTE KARYOMEGALY; KUPFFER CELL PIGMENTATION SPLEEN: HEMATOPOIETIC CELL PROLIFERATION; PIGMENTATION; LYMPHOID FOLLICLE ATROPHY BONE MARROW: HYPERPLASIA KIDNEY: PIGMENTATION EPIDIDYMIS: CHRONIC ACTIVE INFLAMMATION; SPERM GRANULOMA TESTES: GERMINAL EPITHELIAL ATROPHY

Female Mice: Some Evidence

Type	Organ/Tissue (Lesion)
Neoplastic Lesions	Liver: ADENOMA 3/50 4/49 6/49 10/50
Non-Neoplastic Lesions	THYROID GLAND: FOLLICULAR CELL HYPERPLASIA; FOLLICULAR CELL HYPERTROPHY SPLEEN: HEMATOPOIETIC CELL PROLIFERATION; PIGMENTATION