Sunday, June 24, 2012

Hereditary Breast and Ovarian Cancer

Breast and ovarian cancers are among the most common cancers for women. Indeed, more than 12% of women will be affected by breast cancer during their lifespan. Breast cancer can be an invasive cancer; ovarian cancer has one of the highest mortality rates. Both breast cancer and ovarian cancer can occur more frequently in individuals who have an inherited genetic mutation. If an individual has a mutation in his or her BRCA1 or BRCA2 gene, her chance of getting breast cancer increases to 60%. This astonishing five-fold increase is due to the way the mutation changes the body’s responses.


(Image from: The roles of BRCA1 and BRCA2 in DNA repair )



Mutated BRCA1 and BRCA2 do not only affect the breast, nor does BRCA1 or BRCA2 only affect women. Men who have BRCA2 are considerably more likely to develop male breast cancer, pancreatic cancer and prostate cancer at an early age. Indeed, families who have the BRCA1 or BRCA2 mutation have a much greater risk of many types of cancer including uterine, cervical, pancreatic, testicular and other cancers.

Breast and ovarian cancers devastate families and are the subjects of worldwide research studies to determine the link between the BRCA1/BRCA2 mutation and the incidence of early-onset cancers. Studies have found that breast and ovarian cancer as a result of BRCA1 or BRCA2 mutations occur most common in families who have a history of many incidences of breast and ovarian cancer, or in families who have a history of cancer that appears in more than just one site in the body. BRCA1 and BRCA2 mutations also occur more frequently in families from a Central/ Eastern European Jewish background.

With treatment, breast and ovarian cancers can be treatable. While tests to determine whether or not one has the BRCA1/BRCA2 gene mutation are costly, the information they yield can be invaluable to the individual. With proper preventative screenings and tests, one can help identify potentially deadly cancers early enough for intervention.

Function of the BRCA1 Gene


Located on chromosome 17, BRCA1 serves a vital purpose in the body: it suppresses tumor growth by providing the code for a protein that repairs DNA. DNA is arranged in a tight double-helix formation that uses supportive bridges to maintain its shape. When these bridges are removed as happens during replication, the DNA strand can become damaged and requires repair. Other means by which DNA may become damaged includes exposures to environmental toxins and radiation. Damaged DNA causes cells to improperly use their safeguards, and as a result, the cellular differentiation can proliferate out of control, creating tumors.

Healthy BRCA1 works to curb this wild growth because it mends the damage in DNA double helices. In the nucleus of the cell, BRCA1 works with other proteins such as those created by the genes RAD51 and BARD1 to determine the types of breaks and then repair them. Damaged DNA sometimes becomes damaged when DNA is damaged, it responds with the potential for hypertrophy in cells and tissues. This uncontrolled growth creates tumors, and in some cases malignancies. BRCA1’s protein, therefore, protects the integrity of the cell’s blueprint by repairing damage to the structure of the DNA. When BRCA1 becomes mutated, DNA can no longer be repaired, resulting in cancerous growths.
When an individual has a mutated BRCA1, its structural differences create limitations in the gene’s functional ability to create the protein that helps to repair the DNA damage. This leaves the cell prone to dysplasia and hyperplasia, which can eventually lead to tumor growth and a diagnosis of cancer in the affected area of the body. With BRCA1, the tumors are typically associated with the breasts and ovaries.

Mutations in Other Genes


In addition to BRCA1 and BRCA2, mutations in other genes may play a part in inherited predispositions to breast and ovarian cancers. These genes include CHD1, TP53, PTEN, STK11 and others. While these genes might also play an important role in the tendency toward breast cancer, the vast majority of hereditary breast cancers can be traced to a mutation in BRCA1 or BRCA2. These deadly mutations can be identified in 10 to 15 percent of all diagnoses of ovarian cancer and in 5 to 10 percent of all diagnoses of breast cancer. Because of the invasive and potentially fatal effects of mutations in BRCA1 and BRCA2, scientists center their studies on BRCA1 and BRCA2.


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