Initial Causes
Breast cancer is due to mutations within the DNA of normal breast cells that encourage abnormal cell reproduction or limit the ability of the cell to control growth, resulting in tumors. The exact trigger that begins this process and causes an individual's breast cancer is not always known. However, several factors have been shown to increase the risk.
Genetic Influences
Tumor suppressors, named BRCA1 and BRCA2, are genes that help prevent the formation of cancerous tumors. If they are damaged, the cells can grow unchecked. These defective genes that allow breast cancer to begin can be passed through families. Tests are available to show the presence or absence of these tumor suppressors and can be used to help determine the risk for a person whose family history implies a risk that she'll inherit the defective genes. The risk is doubled if a woman has a close female relative--mother, daughter or sibling--with breast cancer. Although young women can also be diagnosed with breast cancer, the chances of getting the disease increase with age, especially over the age of 55. Caucasians have a slightly increased risk of the disease than African-Americans. Although breast cancer is considered a woman's disease and occurs in women most frequently, the disease can also occur in men.
Lifestyle Issues
Certain lifestyle factors have been shown to represent an increased risk of breast cancer, however, they do not determine precisely who will or won't have cancer. One significant risk factor occurred when pregnant women were treated with diethylstilbestrol (DES). The women and their daughters have a higher risk of breast cancer. Hormones and hormone therapy seem to increase the risk of breast cancer. This includes women who had a long period of menstruation (early onset and late menopause), and those who were not pregnant or did not have children until late in life. Birth control pills increase the risk while being taken but the risk appears to diminish after use stops. Hormone replacement therapy for menopause can increase risk. Overweight, lack of exercise, and alcohol use also appear to increase the risk and the American Cancer Society recommends a woman limit herself to one drink per day.
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