International Agency for Research on Cancer (IARC) - Summaries & Evaluations


VOL.: 3 (1973) (p. 91)

5. Summary of Data Reported and Evaluation

5.1 Animal carcinogenicity data

Benzo(a)pyrene has produced tumours in all of the nine species for which data are reported following different administrations including oral, skin and intratracheal routes. It has both a local and a systemic carcinogenic effect. In sub-human primates, there is convincing evidence of the ability of benzo(a)pyrene to produce local sarcomas following repeated subcutaneous injections and lung carcinomas following intratracheal instillation. It is also an initiator of skin carcinogenesis in mice, and it is carcinogenic in single-dose experiments and following prenatal exposure.

In skin carcinogenesis studies in mice benzo(a)pyrene was consistently found to produce more tumours in a shorter period of time than did other polycyclic aromatic hydrocarbons, with the possible exception of dibenzo(a,h)anthracene (see other monographs published in this volume). In a dose-response study involving subcutaneous injection in mice, the minimal dose at which carcinogenicity was detected was higher for benzo(a)pyrene than for dibenzo(a,h)anthracene and for 3-methylcholanthrene. However, the latent periods were shorter for benzo(a)pyrene than for dibenzo(a,h)anthracene. In studies using intratracheal administration, benzo(a)pyrene appeared to be less effective than 7H-dibenzo(c,g)carbazole in the hamster.

5.2 Human carcinogenicity data

No epidemiological studies on the significance of benzo(a)pyrene exposure to man are available, and the studies reported in section 3.3 are insufficient to prove that B(a)P is carcinogenic for man. However, coal-tar and other materials which are known to be carcinogenic to man may contain benzo(a)pyrene. The substance has also been detected in other environmental situations. The possible contribution of polycyclic aromatic hydrocarbons from some environmental sources to the overall carcinogenic risk to man is discussed in the General Remarks. Similarities of metabolism of benzo(a)pyrene in human and mouse cells cultured in vitro have been reported. The relevance of this finding for evaluating the risk for man cannot yet be assessed.

Subsequent evaluations: Vol. 32 (1983); Suppl. 7 (1987) (p. 58: Group 2A)

For definition of Groups, see Preamble Evaluation.

Last updated: 16 March 1998

    See Also:
       Toxicological Abbreviations
       Benzo(a)pyrene (ICSC)