of Health and Human Services released its Eleventh Edition of the Report
on Carcinogens today, adding seventeen substances to the growing list of
cancer-causing agents, bringing the total to 246. For the first time
ever, viruses are listed in the report: hepatitis B virus, hepatitis C
virus, and some human papillomaviruses that cause common sexually
transmitted diseases. Other new listings include lead and lead
compounds, X-rays, compounds found in grilled meats, and a host of
substances used in textile dyes, paints and inks.
residents, 1 in 2 men and 1 in 3 women will develop cancer at some point
in their lifetimes. Research shows that environmental factors trigger
diseases like cancer, especially when someone has a family history,"
said Kenneth Olden, Ph.D., director of the National Institute of
Environmental Health Sciences and the National Toxicology Program, which
prepared the report for HHS.
The Report on
Carcinogens, Eleventh Edition, referred to as the "RoC," lists
cancer-causing agents in two categories -- "known to be human
carcinogens" and "reasonably anticipated to be human carcinogens." The
report now contains 58 "known" and 188 "reasonably anticipated"
listings. Federal law requires the Secretary of the Department of Health
and Human Services to publish the report every two years.
have been added to the "known" category:
virus (HBV) and hepatitis C virus (HCV) are viruses that cause acute or
chronic liver disease. They are listed in the report as "known human
carcinogens" because studies in humans show that chronic hepatitis B and
hepatitis C infections cause liver cancer. Approximately one million
United States residents are chronically infected with HBV, which
primarily is transmitted through sexual contact (50%) and intravenous
drug use (15%).
HCV is the leading cause of liver disease in the United States with more
than three million people infected. The major risk factor for hepatitis
C infection is illegal intravenous drug use, which accounts for 60
percent of acute infections in adults. The incidence of both hepatitis B
and hepatitis C infections is decreasing among United States residents.
A vaccine is available for preventing hepatitis B infection but not
hepatitis C infection. Infections can also be prevented by screening
blood supplies, and by reducing contact with contaminated fluids in
health care settings.
Human papillomaviruses (HPVs) are viruses that are sexually transmitted and
can infect genital and mucous membranes. Some of these genital mucosal
type HPVs are listed in the report as "known human carcinogens" because
studies show they cause cervical cancer in women. Approximately 20
million people in the United States are infected with genital HPVs, and
5.5 million new infections occur each year. Most people infected do not
have symptoms, but some develop genital warts or cervical abnormalities.
and gamma-radiation are listed in the report as "known human
carcinogens" because human studies show that exposure to these kinds of
radiation causes many types of cancer including leukemia and cancers of
the thyroid, breast and lung. The risk of developing cancers due to
these forms of ionizing radiation depends to some extent on age at the
time of exposure. Childhood exposure is linked to an increased risk for
leukemia and thyroid cancer. Exposure during reproductive years
increases the risk for breast cancer, and exposure later in life
increases risk for lung cancer. Exposure to X-radiation and gamma
radiation has also been shown to cause cancer of the salivary glands,
stomach, colon, bladder, ovaries, central nervous system and skin.
total worldwide exposure to X-radiation and gamma-radiation, 55 percent
is from low-dose medical diagnosis such as bone, chest and dental
X-rays, and 43 percent is from natural sources like radon. Other
sources, such as industry, scientific research, military weapons
testing, nuclear accidents and nuclear power generation, account for
about 2 percent.
also listed in the report as a "known human carcinogen." They cause
genetic damage similar to that of X-radiation and gamma radiation, and
thus can cause the same cancers. Neutron radiation is used less than
other types of radiation in industry, medicine, and research. The
general population is exposed to neutrons primarily from cosmic
radiation that penetrates the earth's atmosphere.
Eleven substances have been added to the "reasonably anticipated"
is used as an intermediate in the synthesis of many industrial
chemicals, and has been used as an ingredient in some moth repellants
and toilet bowl deodorants. Naphthalene is listed in the report as
"reasonably anticipated to be a human carcinogen," based on inhalation
studies in animals which showed it causes rare nasal tumors in rats and
benign lung tumors in female mice.
and PhIP are heterocyclic amine compounds formed when meats and eggs are
cooked or grilled at high temperatures. These compounds are also found
in cigarette smoke. They are listed in the report as "reasonably
anticipated to be human carcinogens" because oral studies in animals
showed they caused cancer in multiple organs including the forestomach,
colon, liver, oral cavity, mammary gland, skin, and cecum. Several human
studies suggest there is an increased risk for breast and colorectal
cancers related to consumption of broiled or fried foods that may
contain these or other similar compounds.
2-Amino-3, 4-dimethylimidazo [4,5-f]quinoline
MeIQx is 2-Amino-3, 8-dimethylimidazo [4,5-f]quinoxaline
PhIP is 2-Amino-1-methyl-6-phenylimidazo [4,5-b]pyridine
Lead is used
to make lead-acid storage batteries, ammunition, and cable coverings.
Lead compounds are used in paint, glass and ceramics, fuel additives,
and in some ethnic and ceremonial cosmetics. The report lists lead and
lead compounds as "reasonably anticipated to be human carcinogens"
because exposure to lead or lead compounds is associated with a small
increased risk for lung or stomach cancer in humans, and cancer of the
kidney, brain or lung in studies with laboratory animals.
Sulfate is used in electroplating, as coloring agents for ceramics, and
as drying agents in inks and paints. Cobalt sulfate is listed as
"reasonably anticipated to be a human carcinogen" based on inhalation
studies in laboratory animals that showed it causes adrenal gland and
Diazoaminobenzene is a chemical used as an intermediate in the
production of dyes and to promote adhesion of natural rubber to steel.
Diazoaminobenzene is listed as "reasonably anticipated to be a human
carcinogen" based on evidence that it is metabolized to benzene, a
"known human carcinogen," and because it causes genetic damage in
is a chemical used mainly in the production of other industrial
chemicals. It is listed as "reasonably anticipated to be a human
carcinogen" because inhalation studies of this compound produced cancer
in experimental animals.
4-dibromoanthraquinone is a vat dye that is used in the textile
industry. It is listed as "reasonably anticipated to be a human
carcinogen" based on evidence that it causes cancer in experimental
4,4'-Thiodianiline has been used as an intermediate in the preparation
of several kinds of dyes. It is listed as "reasonably anticipated to be
a human carcinogen" based on evidence that it causes cancer in
is used in specialized fuels, explosives, and in the synthesis of
pharmaceuticals and agricultural chemicals. It is listed as "reasonably
anticipated to be a human carcinogen" based on evidence that it causes
cancer in experimental animals.
The Report on
Carcinogens, Eleventh Edition, is prepared by the National Toxicology
Program, an interagency group coordinated by the U.S. Department of
Health and Human Services. The full report is available at the NTP
Toxicology Program is located at the National Institute of Environmental
Health Sciences (NIEHS) in Research Triangle Park, NC. Part of the
National Institutes of Health, NIEHS looks at factors in the environment
that may be harmful to human health.