National Toxicology Program

National Toxicology Program

Scientific Review of Heterocyclic Amines (Selected): PhIP, MeIQ, and MeIQx

2-Amino-3,4-dimethylimidazo [4,5-f]quinoline (MeIQ) - CASRN 77094-11-2
2-Amino-3,8-dimethylimidazo [4,5-f]quinoxaline (MeIQx) - CASRN 77500-04-0
2-Amino-1-methyl-6- phenylimidazo [4,5-b]pyridine (PhIP) - CASRN 105650-23-5

Status: Listed in the Report on Carcinogens (RoC)

Primary Uses or Exposures: MeIQ, MeIQx, and PhIP are part of a series of heterocyclic amines (HCAs) that are formed in food during heating or cooking at high temperatures and are found in cooked meats and eggs and also in cigarette smoke. The RoC listing of these selected heterocyclic amines is based on findings from oral studies in multiple species of experimental animals that showed cancer in multiple organs including forestomach, cecum, colon, liver, oral cavity, Zymbal gland, mammary gland, and skin. Although evidence from human epidemiology suggests that consumption of well-done or grilled meat (which may contain these and/or other HCAs) may be associated with increased cancer risk in humans, the data are insufficient to support the conclusion that this risk is due specifically to MeIQx, MeIQ or PhIP present in these foods.

Background Document

Public Comments

Meetings and Minutes from Review Groups

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NTP is located at the National Institute of Environmental Health Sciences, part of the National Institutes of Health.