The Carcinogenic Potency Database (CPDB)
Lois Swirsky Gold, PhD, Director
Memorial of Lois Swirsky Gold
A Web page (Margin of Exposure) provides a broad perspective on
possible cancer hazards from human exposures to chemicals that
cause cancer in high dose rodent cancer tests. Exposures are given
in graphic and table
formats, including high historical exposures to workers,
pharmaceuticals, natural chemicals in the average diet, air
pollutants, food additives, and pesticide residues.
A supplement to the CPDB was added in August 2007,
which includes results on 66 new chemicals and new results for 52
chemicals already in the CPDB. All Web pages on this Web site have
been updated to reflect these additions, including plots, summary
tables, and Excel files. Click here for a
list of new chemicals and a list of earlier chemicals with new
data.
The Carcinogenic Potency Database (CPDB) is a
unique and widely used international resource of the results of
6540 chronic, long-term animal cancer tests on 1547 chemicals. The
CPDB provides easy access to the bioassay literature, with
qualitative and quantitative analyses of both positive and negative
experiments that have been published over the past 50 years in the
general literature through 2001 and by the National Cancer
Institute/National Toxicology Program through 2004. The CPDB
standardizes the diverse literature of cancer bioassays that vary
widely in protocol, histopathological examination and nomenclature,
and in the published author’s choices of what information to
provide in their papers. Results are reported in the CPDB for tests
in rats, mice, hamsters, dogs, and nonhuman primates.
For each experiment, information is included that
is important in the interpretation of bioassays: species, strain,
and sex of test animal; features of experimental protocol such as
route of administration, duration of dosing, average daily
dose-rate in mg/kg body weight/day, and duration of experiment;
target organ, tumor type, and tumor incidence; carcinogenic potency
(TD50) and its statistical significance; shape of the
dose-response, author’s opinion as to carcinogenicity, and
literature citation. The TD50,
our numerical description of carcinogenic potency, is the daily
dose-rate in mg/kg/body weight/day for life to induce tumors in
half of test animals that would have remained tumor-free at zero
dose. TD50 provides a standardized quantitative measure
that can be used for comparisons and analyses of many issues in
carcinogenesis. The range of TD50 values across
chemicals that are rodent carcinogens is more than 100
million-fold.
A description of methods used in the CPDB to
standardize the diverse literature of animal cancer tests is
presented for:
The boxes above link to several formats of the
CPDB that are suitable for (1) screen viewing, (2) printing or (3)
reading the data into statistical packages and spreadsheets. Codes
used in the CPDB are defined in appendices. The Web site is fully
searchable by all fields and includes SMILES, InChI codes and
structures for all chemicals.
A summary table by chemical reports a one-line
summary of positivity, potency and target sites for each chemical,
whether positive or negative for carcinogenicity. A compendium of
CPDB results organized by target organ reports all chemicals that
induce tumors in each of 35 target organs.
A single Web page on each chemical gives all
results in the CPDB.
Estimates of the lower confidence on TD10 are provided in an
Excel spreadsheet.
The Web site provides a
single Web page on each individual
chemical in the CPDB, which is accessible from a list of chemicals.
These Web pages of individual chemicals provide both summary and
complete information about each chemical in the CPDB. Each page
reports a summary of results for that chemical in each sex-species
tested, including positivity, target sites and TD
50
values. Detailed results from each experiment on that particular
chemical are given in a plot format suitable for screen viewing.
Chemical structure, InChI and SMILES codes are reported.
A new web page presents a
graphic that uses a Margin of Exposure Index to
provide a broad perspective on possible cancer hazards from human
exposures to chemicals that cause cancer in high dose rodent cancer
tests. Exposures include high historical exposures to workers,
pharmaceuticals, natural chemicals in the average diet, air
pollutants, food additives, and pesticide residues. Human exposure
levels range from close to the rodent carcinogenic dose for a few
historical exposures in the workplace to a billion times less the
rodent carcinogenic dose for some pesticide residues. Human
consumption of the background of natural chemicals in food is
usually closer to the rodent carcinogenic dose than pesticide
residues or pollutants, and half the natural chemicals tested are
carcinogenic in high dose tests. Recent risk assessment methods
indicate that for some chemicals the mechanism of carcinogenesis in
rodents at high dose is not relevant to humans.
Our publications are provided as PDF files on
this Web site, listed
by year
and
by topic. Broad research
areas include: methodological analyses of bioassay results; species
comparisons in carcinogenicity and potency; target organs of
chemical carcinogens; mechanisms of carcinogenesis and the
interpretation of the high proportion of chemicals that test
positive; risk assessment techniques; the background of
naturally-occurring chemicals that are rodent carcinogens; setting
priorities among possible cancer hazards from natural and synthetic
rodent carcinogens; occupational exposures and possible cancer
hazards; disparities in cancer risk estimates for pesticide
residues in food; and misconceptions about the causes of
cancer.
The CPDB was developed between 1980 and 2005 by
the following people:
Lois Swirsky Gold, Bruce N. Ames, Leslie
Bernstein, Mark Blumenthal, Kenneth Chow, Maria Da Costa, Margarita
de Veciana, Susan Eisenberg, Georganne Backman Garfinkel, Thomas
Haggin, William R. Havender, N. Kim Hooper, Robert Levinson, Peggy
Lopipero, Renae Magaw, Neela B. Manley, Peter M. MacLeod, Richard
Peto, Malcolm C. Pike, Lars Rohrbach, Charles B. Sawyer, Thomas H.
Slone, Mark Smith, Bonnie R. Stern, Michael Wong.
Last updated:
September 1, 2011
td50, database, cancer risk, natural chemical
pesticide, cancer, carcinogen, tumor, chemical, herp, hert, perp,
bioassay, coffee, pollution, misconception, maximum tolerated dose,
carcinogenesis, cooking, heterocyclic amine, lifetable, occupation,
regulation, risk assessment
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