What is BRCA1?
BRCA1 is human gene that belong to a class of genes known as tumor suppressors. In normal cells, BRCA1 helps ensure the stability of the cell’s genetic material (DNA) and helps prevent uncontrolled cell growth. Mutation (Malfunction) of this gene has been linked to the development of hereditary breast and ovarian cancer. The names BRCA1 stand for BReast CAncer susceptibility gene 1
How does BRCA1 gene mutation affect a person's risk of cancer?
Not all gene changes, or mutations, are deleterious (harmful-but mine is). Some mutations may be beneficial, whereas others may have no obvious effect (neutral). Harmful mutations can increase a person’s risk of developing a disease, such as cancer.
A woman’s lifetime risk of developing breast and/or ovarian cancer is greatly increased if she inherits a harmful mutation in BRCA1. Such a woman has an increased risk of developing breast and/or ovarian cancer at an early age (before menopause) and often has multiple, close family members who have been diagnosed with these diseases. Harmful BRCA1 mutations may also increase a woman’s risk of developing cervical, uterine, pancreatic, and colon cancer (1, 2). Men with harmful BRCA1 mutations also have an increased risk of breast cancer and, possibly, of pancreatic cancer, testicular cancer, and early-onset prostate cancer.
The likelihood that a breast and/or ovarian cancer is associated with a harmful mutation in BRCA1 is highest in families with a history of multiple cases of breast cancer, cases of both breast and ovarian cancer, one or more family members with two primary cancers (original tumors that develop at different sites in the body), However, not every woman in such families carries a harmful BRCA1 mutation, and not every cancer in such families is linked to a harmful mutation in one of these genes. Furthermore, not every woman who has a harmful BRCA1 mutation will develop breast and/or ovarian cancer.
What does a positive BRCA1 or BRCA2 test result mean?
A positive test result generally indicates that a person has inherited a known harmful mutation in BRCA1 and, therefore, has an increased risk of developing certain cancers, as described above. However, a positive test result provides information only about a person’s risk of developing cancer. It cannot tell whether an individual will actually develop cancer or when. Not all women who inherit a harmful BRCA1 mutation will develop breast or ovarian cancer.
A positive genetic test result may have important health and social implications for family members, including future generations. Unlike most other medical tests, genetic tests can reveal information not only about the person being tested but also about that person’s relatives. Both men and women who inherit harmful BRCA1 mutations, whether they develop cancer themselves or not, may pass the mutations on to their sons and daughters. However, not all children of people who have a harmful mutation will inherit the mutation.
What are the options for a person who has a positive test result?
Several options are available for managing cancer risk in individuals who have a harmful BRCA1 mutation. However, high-quality data on the effectiveness of these options are limited.
- Surveillance—Surveillance means cancer screening, or a way of detecting the disease early. Screening does not, however, change the risk of developing cancer. The goal is to find cancer early, when it may be most treatable.
Surveillance methods for breast cancer may include mammography and clinical breast exams. Studies are currently under way to test the effectiveness of other breast cancer screening methods, such as magnetic resonance imaging (MRI), in women with BRCA1 mutations. With careful surveillance, many breast cancers will be diagnosed early enough to be successfully treated.
For ovarian cancer, surveillance methods may include transvaginal ultrasound, blood tests for CA–125 antigen, and clinical exams. Surveillance can sometimes find ovarian cancer at an early stage, but it is uncertain whether these methods can help reduce a woman's chance of dying from this disease.
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