The IARC monographs program: changing attitudes towards public health.

From its outset, the International Agency for Research on Cancer's (IARC's) program for the evaluation of carcinogenic risks for humans had to resist strong direct and indirect pressures from various sources to protect its independence. External experts for Monographs working groups were selected on the basis of competence and the absence of conflicts of interest. The IARC did not use unpublished or confidential data, so readers could access the original information and thus follow the groups' reasoning. The strength of the original program lay in its scientific integrity and its transparency. Since 1994, however, the IARC appears to have attributed less importance to public health-oriented research and primary prevention, and the Monographs program seems to have lost some of its independence. Criteria for evaluating carcinogenicity related to mechanism(s) of action are not necessarily used as originally intended, to ensure better protection of public health. Evidence for carcinogenicity provided by the results of experimental bioassays has been disregarded on the basis of only suggested mechanistic hypotheses. If tests show those hypotheses to be incorrect, or if they do not account adequately for the wide range of susceptibility in humans, serious consequences for public health may follow.