CHEMICAL CARCINOGENS

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CHEMICAL CARCINOGENS
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What is a Chemical Carcinogen?

• Any chemical compound which has been shown to
  cause cancer in humans or in animal studies.
• Hundreds of individual compounds have been shown
  to induce cancers. Many thousands of additional
  compounds are suspect carcinogens.
• Many are commonly used in laboratory procedures,
  manufacturing, and in industry.
• Most cause localized base changes in DNA
  (exceptions are asbestos and diethylstilbestrol)

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Categories of Known Human Carcinogens

• Chemicals (organic and inorganic)
• Agents encountered in occupational exposure
  (e.g., benzene)
• Drug Therapies (particularly chemotherapy)
• Environmental agents (UV light, asbestos, and
  tobacco)

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Chemical Carcinogens
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Chemical Carcinogens Continued
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Chemical Carcinogens Continued
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How is Chemical Carcinogenicity Determined?

• Epidemiological studies determine the
  relationship between a cancer suspect chemical
  and a human population over a long period of
  time.
• Animal studies directly induce cancer in test
  animals using a large sample of animals, usually
  of two or more species with varying dose and time
  parameters.
• Experiments with animals are based on the premise
  that chemicals that produce cancer in animals
  will have similar effects on human cells. Most
  known human carcinogens produce cancer in
  experimental animals.

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Ames Test for Carcinogenicity
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How do Carcinogens Enter the Body?

• Skin absorption.
• Ingestion. Swallowing of a carcinogen.
• Inhalation. Breathing gases, fumes, and vapors
  is the most common form of exposure.

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What Organs do Carcinogens Most Frequently
Attack?

• Lungs
• Liver
• Kidney
• Reproductive system
• Skin
• Many other organs and tissues

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What Factors Influence the Development of Cancer?

• Dose - amount and duration of exposure. The
  lower the dose the least likely you are to
  develop cancer or related diseases.
• Environmental or lifestyle factors
• Cigarette smoking (co-carcinogen)
• Alcohol consumption (co-carcinogen)
• Diet - high fat consumption, low fiber
• Fitness level
• Age, race, and gender
• Geographic location - industrial areas, UV light
• Inherited conditions (Xeroderma pigmentosum) and
  genetic makeup

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How Can One Reduce Their Exposure to Carcinogens?
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Minimizing Ones Exposure to Carcinogens

• General room ventilation - 10 or more changes of
  air per hour. Designed to reduce exposures below
  the permissible exposure limit.
• Fume hoods.
• Local ventilation - exhaust (sometimes supply) at
  the point of use of a chemical.
• Biosafety cabinet--used for anticancer drugs,
  viruses.
• No bench top work in a laboratory setting.

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Personal Protective Equipment

• Respiratory protection - dust masks, respirators.
  Respirators are primarily for use in non-lab
  areas, except for emergency response (spill
  cleanup)--shops, floor stripping, construction
  operations (painting).
• Eye protection - safety glasses, splash goggles,
  and face shields.
• Hand protection - gloves and protective sleeves.
• Protective clothing - lab coats.

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Personal Hygiene

• No smoking, eating, drinking or application of
  cosmetics is permitted in areas where carcinogens
  are in use (or in any lab area!). No mouth
  pipetting!
• Wash hands and any exposed skin if potentially
  contaminated - face, neck, forearms, etc.
• No shorts or open-toed shoes.
• Remove lab coat or other potentially contaminated
  protective clothing before leaving the work area.
  Lab coats need to be cleaned regularly.
• Contaminated disposable clothing should be
  treated as hazardous waste.

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Labeling of Containers

• All containers of chemical carcinogens need to
  have a warning label affixed to them.
• DANGER Contains ___________
  CANCER HAZARD

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Storage of Carcinogens

• Carcinogens must be stored separately from other
  materials.
• Separated by shelving system or secondary
  containment.
• Storage areas must be labeled Danger--Carcinogens
  Stored Here.

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Disposal of Carcinogen Waste Materials

• All contaminated substances (paper towels,
  supplies, etc.) must be properly labeled and sent
  out for incineration as Regulated Medical Waste
• Carcinogens may never be disposed of in the
  ordinary trash.
• Dry wastes must be autoclaved and shipped out as
  regulated medical waste (Chemotherapeutic
  Agents).

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Ultimate Goals

• Determine the various mechanisms by which known
  carcinogens act and to identify the function of
  specific genes that confer increased
  susceptibility, or which are the targets of
  environmental carcinogens.