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| DiseaseID |
HGD63 |
| Genetic
Disorder |
Breast_cancer
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| Gene
Name |
BRCA1 interacting protein C-terminal helicase 1 |
| Description |
Breast cancer is a common disease. Each year, approximately 200,000 women in the United States are diagnosed with breast cancer, and one in nine American women will develop breast cancer in her lifetime. But hereditary breast cancer - caused by a mutant gene passed from parents to their children - is rare. Estimates of the incidence of hereditary breast cancer range from between 5 to 10 percent to as many as 27 percent of all breast cancers. In 1994, the first gene associated with breast cancer - BRCA1 (for BReast CAncer1) was identified on chromosome 17. A year later, a second gene associated with breast cancer - BRCA2 - was discovered on chromosome 13. When individuals carry a mutated form of either BRCA1 or BRCA2, they have an increased risk of developing breast or ovarian cancer at some point in their lives. Children of parents with a BRCA1 or BRCA2 mutation have a 50 percent chance of inheriting the gene mutation.
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| Symptoms |
The first symptom, or subjective sign, of breast cancer is typically a lump that feels different than the surrounding breast tissue. According to the Merck Manual, greater than 80% of breast cancer cases are discovered as a lump by the woman herself. According to the American Cancer Society (ACS), the first medical sign, or objective indication of breast cancer as detected by a physician, is discovered by mammogram. Lumps found in lymph nodes located in the armpits and/or collarbone can also indicate breast cancer. Indications of breast cancer other than a lump may include changes in breast size or shape, skin dimpling, nipple inversion, or spontaneous single-nipple discharge. Pain is an unreliable tool in determining the presence of breast cancer, but may be indicative of other breast-related health issues such as mastodynia. When breast cancer cells invade the dermal lymphatics, small lymph vessels in the skin of the breast, its presentation can resemble skin inflammation and thus is known as inflammatory breast cancer (IBC). Symptoms of inflammatory breast cancer include pain, swelling, warmth and redness throughout the breast, as well as an orange peel texture to the skin referred to as peau d'orange. Another reported symptom complex of breast cancer is Paget's disease of the breast. This syndrome presents as eczematoid skin changes such as redness and mild flaking of the nipple skin. As Paget's advances, symptoms may include tingling, itching, increased sensitivity, burning, and pain. There may also be discharge from the nipple. Approximately half of women diagnosed with Paget's also have a lump in the breast. Occasionally, breast cancer presents as metastatic disease, that is, cancer that has spread beyond the original organ. Metastatic breast cancer will cause symptoms that depend on the location of metastasis. More common sites of metastasis include bone, liver, lung and brain. Unexplained weight loss can occasionally herald an occult breast cancer, as can symptoms of fevers or chills. Bone or joint pains can sometimes be manifestations of metastatic breast cancer, as can jaundice or neurological symptoms. These symptoms are "non-specific," meaning they can also be manifestations of many other illnesses. Most symptoms of breast disorder do not turn out to represent underlying breast cancer. Benign breast diseases such as mastitis and fibroadenoma of the breast are more common causes of breast disorder symptoms. The appearance of a new symptom should be taken seriously by both patients and their doctors, because of the possibility of an underlying breast cancer at almost any age.
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| Causes |
In breast cancer, some of the cells in your breast begin growing abnormally. These cells divide more rapidly than healthy cells do and may spread (metastasize) through your breast, to your lymph nodes or to other parts of your body. The most common type of breast cancer begins in the milk-producing ducts, but cancer may also begin in the lobules or in other breast tissue.
In most cases, it isn't clear what causes normal breast cells to become cancerous. Doctors do know that only 5 percent to 10 percent of breast cancers are inherited. Families that do have genetic defects in one of two genes, breast cancer gene 1 (BRCA1) or breast cancer gene 2 (BRCA2), have a much greater risk of developing both breast and ovarian cancer. Other inherited mutations — including the ataxia-telangiectasia mutation gene, the cell-cycle checkpoint kinase 2 (CHEK-2) gene and the p53 tumor suppressor gene — also make it more likely that you'll develop breast cancer. If one of these genes is present in your family, you have a 50 percent chance of having the gene.
Yet most genetic mutations related to breast cancer aren't inherited. These acquired mutations may result from radiation exposure — women treated with chest radiation therapy for lymphoma in childhood or during adolescence when breasts are developing have a significantly higher incidence of breast cancer than do women not exposed to radiation. Mutations may also develop as a result of exposure to cancer-causing chemicals, such as the polycyclic aromatic hydrocarbons found in tobacco and charred red meats.
Researchers are now trying to discover whether a relationship exists between a person's genetic makeup and environmental factors that may increase the risk of breast cancer. Breast cancer eventually may prove to have a number of causes. |
| Diagnosis |
Breast cancer is diagnosed by the examination of surgically removed breast tissue. A number of procedures can obtain tissue or cells prior to definitive treatment for histological or cytological examination. Such procedures include fine-needle aspiration, nipple aspirates, ductal lavage, core needle biopsy, and local surgical excision. These diagnostic steps, when coupled with radiographic imaging, are usually accurate in diagnosing a breast lesion as cancer. Occasionally, pre-surgical procedures such as fine needle aspirate may not yield enough tissue to make a diagnosis, or may miss the cancer entirely. Imaging tests are sometimes used to detect metastasis and include chest X-ray, bone scan, Cat scan, MRI, and PET scanning. While imaging studies are useful in determining the presence of metastatic disease, they are not in and of themselves diagnostic of cancer. Only microscopic evaluation of a biopsy specimen can yield a cancer diagnosis. Ca 15.3 (carbohydrate antigen 15.3, epithelial mucin) is a tumor marker determined in blood which can be used to follow disease activity over time after definitive treatment. Blood tumor marker testing is not routinely performed for the screening of breast cancer, and has poor performance characteristics for this purpose.
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| Treatment |
The mainstay of breast cancer treatment is surgery when the tumor is localized, with possible adjuvant hormonal therapy (with tamoxifen or an aromatase inhibitor), chemotherapy, and/or radiotherapy. At present, the treatment recommendations after surgery (adjuvant therapy) follow a pattern. This pattern is subject to change, as every two years, a worldwide conference takes place in St. Gallen, Switzerland, to discuss the actual results of worldwide multi-center studies. Depending on clinical criteria (age, type of cancer, size, metastasis) patients are roughly divided to high risk and low risk cases, with each risk category following different rules for therapy. Treatment possibilities include radiation therapy, chemotherapy, hormone therapy, and immune therapy. In planning treatment, doctors can also use PCR tests like Oncotype DX or microarray tests like MammaPrint that predict breast cancer recurrence risk based on gene expression. In February 2007, the MammaPrint test became the first breast cancer predictor to win formal approval from the Food and Drug Administration. This is a new gene test to help predict whether women with early-stage breast cancer will relapse in 5 or 10 years, this could help influence how aggressively the initial tumor is treated. |
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