Breast Cancer, Genes, and the Environment

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Breast Cancer, Genes, and the Environment

• UNC-Chapel Hill
• Center for Environmental Health and Susceptibility

Funded by the National Institute of Environmental
Health Sciences (NIEHS), P30ES10126 10/2006
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Goals

• To learn about breast cancer risks
• To learn how personal and environmental factors
  may contribute to increased health risk
• To identify risk reduction activities

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Breast Cancer Statistics

• Most common cancer in women
• 2nd leading cause of cancer death

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What Is Breast Cancer?

• Cells in the breast grow abnormally and form a
  lump
• Malignant growths are called breast cancer
• Breast cancer commonly starts in the ducts

Graphic courtesy of www.umm.edu/breast/anatomy.htm

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Genes and Cancer
Acquired Damage Wear and Environment
Diet
Chemicals
Radiation
Genes are sections of DNA
Heredity
Inherited Damage
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Risk Factors for Breast Cancer
Environmental
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Estrogen-Related Risk Factors

• Early menstruation
• Before 12 yrs old? increased risk
• Late menopause
• After 55 yrs old? increased risk
• Child bearing
• No children? increased risk
• First child born after age 30? increased risk

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Estrogen-Related Risk Factors

• Breastfeeding
• 12 months? decreased risk
• Oral contraceptives
• Increased risk dissipates since time of last use
• Long-term hormone replacement therapy
• More than 5yrs? increased risk

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Other Personal Risk Factors

• Risk increases with age Being age 55 or
  older
• Having breast cancer previously
• Family history of breast cancer
• Dense breast tissue
• Some types of breast disease

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Family History

• Immediate family member
• more than one with breast cancer at any age
• one with breast or ovarian cancer before 50 or
• one with cancer in both breasts

• Shared genetic makeup
• Similar lifestyle choices and environmental
  exposures

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Environmental Risk Factors Lifestyle Choices

• Alcohol
• One or more drinks/day? increased risk
• Diet
• High in fruits and vegetables? decreased risk

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Environmental Risk Factors Lifestyle Choices

• Exercise
• Regular exercise ? decreased risk
• Weight
• Maintaining healthy weight? decreased risk

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Environmental Risk Factors

• Toxicants can damage breast DNA, which can lead
  to cancer over time.
• Exposure to high doses of radiation, treating
  Hodgkins disease
• Increased risk in women under 30

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Environmental Risk Factors

• Pesticides (DDT) and industrial chemicals (PCBs)
• No association with increased breast
• cancer risk
• Certain women may be more susceptible
• Electromagnetic fields
• No association with increased breast
• cancer risk

Long Island Breast Cancer Study Project,
2002 Carolina Breast Cancer Study, 2001
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Environmental Risk Factors

• By-products of burning (PAHs)
• Created when coal, oil, gas, garbage, or
• other organic substances are burned
• DNA damage ? increased risk
• Smoking
• Active smoking as teenager ? increased risk
• Passive smoking long-term smoking spouse ?
  increased risk

Long Island Breast Cancer Study Project, 2002
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Screening for Breast Cancer

• Early diagnosis increases chance of survival
• Breast self-exam
• Clinical breast exam
• Annual mammogram after age 40

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Questions?

• UNC Center for Environmental Health
• and Susceptibility
• Diana Tarrant
• [phone]
• Diana_Tarrant_at_unc.edu

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Questions?

• UNC Center for Environmental Health
• and Susceptibility
• Kathleen Gray, Director
• Community Outreach and Education Core
• [phone]
• kgray_at_unc.edu