Intrauterine and early postnatal life are periods of exceptionally high susceptibility to certain kinds of chemical carcinogens. The most potent known transplacental carcinogens are direct acting alkylating agents. Most nonreactive compounds, which require enzymes for metabolic conversion into chemically reactive "proximate carcinogens," are less effective because the required enzymes are prese...

The Report on Carcinogens includes two separate listings (i.e., profiles) for cobalt-related exposures: Cobalt and Cobalt Compounds That Release Cobalt Ions In Vivo and Cobalt-Tungsten Carbide: Powders and Hard Metals. Cobalt and cobalt compounds as a class are listed for the first time in the Fourteenth Report on Carcinogens, and this listing includes and supersedes the listing for cobalt sulf...

Perinatal exposure to carcinogens may contribute to the determination of susceptibility to cancer in two situations: a) exposure in utero of embryonal or fetal somatic cells to carcinogens, and b) prezygotic exposure of the germ cells of one or both parents to carcinogens. Epidemiological as well as experimental studies demonstrate that exposure to carcinogens in utero increases the occurrence ...

Implications of not detecting non-genotoxic carcinogens in the absence of carcinogenicity tests under REACH guidelines Research performed by the RIVM has demonstrated that the European legislation does not comply with a specific small group of carcinogens, the so-called non-genotoxic carcinogens, which induce cancer via a mechanism other than the introduction of DNA damage. In view of these fin...

Experimental methods for the identification of chemical carcinogens have been extensively developed, including animal bioassay methods, animal models for cancer induction at major organ sites, models for the study of the effects of carcinogens in cells and tissues in culture and methods for the study of molecular events (metabolic activation, binding and detoxification of carcinogens; DNA damag...

BACKGROUND The use of biological-based markers of exposure, intermediate effect, outcome, and susceptibility has become standard practice in cancer epidemiology, which has contributed to identification of several carcinogenic agents. Nevertheless, with the exception of biological agents, this contribution, in terms of providing sufficiently strong evidence as required by the International Agenc...

Choosing a cost-effective strategy for classifying chemicals as human carcinogens and non-carcinogens depends upon the costs of false positives (carcinogens erroneously treated as non-carcinogenic) and false negatives (non-carcinogens erroneously treated as carcinogenic); upon the accuracy (sensitivity and specificity) of the classification strategy; and upon the underlying proportion of carcin...

Most regulatory agencies assume that there is no safe level of exposure to carcinogens but that a threshold, or “safe” exposure level exists for non-carcinogens. However, recent discoveries have cast serious doubt on the validity of this concept. Five examples of non-carcinogens without an apparent threshold (neonicotinoids, dioxin, dieldrin, endocrine disruptors, and sulfhydryl-reactive metals...

We have previously shown the hepatic gene expression profiles of carcinogens in 28-day toxicity tests were clustered into three major groups (Group-1 to 3). Here, we developed a new prediction method for Group-1 carcinogens which consist mainly of genotoxic rat hepatocarcinogens. The prediction formula was generated by a support vector machine using 5 selected genes as the predictive genes and ...