Breast Cancer : Cancer And Cancer

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Breast Cancer
Disease Overview Breast cancer is a disease in which certain cells in the breast become abnormal and multiply uncontrollably to form a tumor. Breast cancer is the second most commonly diagnosed cancer in women. (Only skin cancer is more common.) About one in eight women in the United States will develop invasive breast cancer in her lifetime. Researchers estimate that more than 230,000 new cases of invasive breast cancer will be diagnosed in U.S. women in 2015. Cancers occur when a buildup of mutations in critical genes—those that control cell growth and division or repair damaged DNA—allow cells to grow and divide uncontrollably to form a tumor. Breast cancer can be caused by inherited genetic factors. These genetic
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By helping to repair DNA, the BRCA2 protein plays a critical role in maintaining the stability of a cell 's genetic information. The cancer risk caused by BRCA2 mutations is inherited in a dominant fashion, even though usually only one mutated allele is directly inherited. This is because people with the mutation are likely to acquire a second mutation, leading to the dominant expression of the cancer. A mutated BRCA gene can be inherited from either parent. Because they are inherited from the parents, they are classified as hereditary or germline mutations. Because humans have a diploid genome, each cell has two copies of the gene (one from each biological parent). Typically only one copy contains a disabling, inherited mutation, so the affected person is heterozygous for the mutation. If the functional copy is harmed, however, then the cell is forced to use alternate DNA repair mechanisms, which are more error-prone. The loss of the functional copy is called loss of heterozygosity (LOH). Any resulting errors in DNA repair may result in cell death or a cancerous transformation of the cell. Disease Pathology High-risk families include those whose members carry a mutation in the BRCA2 gene. The mutated BRCA2 gene is inherited in an autosomal dominant pattern. A child needs to inherit just one copy of the mutated gene to have an increased cancer risk. Children who have a parent with a BRCA2
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