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