Carcinogenicity evaluation and regulatory decisions.

I should first and foremost like to thank our distinguished panel for agreeing to take part in what I am sure will be a landmark session of the Toxicology Forum and our program committee for assembling this excellent group. In a sense it is rather anachronistic that having so often remarked that the Toxicology Forum must make an effort to become broadly based and not appear as though it was a junior section of the American Association of Cancer Research that we are having a basic cancer research review today very much with my personal encouragement. In fact, it is not at all anachronistic; our obvious objective, and I hope it is obvious to all from the format of the program, is to try and place the toxicologists’ “Cancer Problems” into the general perspective of modern cancer research. The carcinogenesis studies undertaken by the toxicologist are not supposed to be research in the pure sense; they are routine prescribed tests that are designed to detect potential human cancer hazards from chemical compounds. As time has gone on I believe that it must have become patently obvious to everyone that the stage is not yet set for us to be able to undertake batteries of “routine tests” and then apply routine assessments and come up with pat answers satisfactory for regulatory purposes. I have found myself repeating a seemingly trite statement over and over again during discussions of various carcinogen tests, namely, that strange as it may seem, the cancer problem has not been solved yet. In any event I do not think that I will find anyone here who will not agree that there are still some problems in cancer research to be solved. There is a crisis in toxicology that is coming to a head, the NTP and the NC1 have been major contributors in causing it; and a good thing too as long as it leads to a proper reevaluation. I believe that there is no question that many compounds about to come into contact with man must be tested in the long term; I also believe that overt