Breast cancer is the result of genetic mutations accumulating in breast tissue cells causing them to grow abnormally quickly. Sporadic mutations occur over the course of the patient's life, whereas inherited ones are passed on from the patient's parents. One type of genetic mutation, known as 13q deletion, can predispose a patient to developing breast cancer.
13Q Deletion
Human DNA is broken up into a number of chromosomes, which can be identified by a number. Each of these chromosomes can then be broken up into different sections, which are often designated by a letter. Thus, the term 13q refers to a specific area on the 13th chromosome that encompasses many different genes. Sometimes during the process of cellular reproduction, small stretches of DNA are lost due to errors in the replication of DNA. This is known as a deletion. Patients with a deletion in 13q are missing some of their DNA in the 13q region of their genetic material.
Tumor Suppressors
Genetic deletions, such as a deletion in 13q, can lead to an increased risk of cancer by inactivating specific genes called tumor suppressors. The National Cancer Institute explains that tumor suppressors are genes that, if damaged or disabled, can lead to cancer. Tumor suppressors may work to repair other mutations in DNA, or they can encode proteins that slow the growth of cells.
BRCA2 and Others
One important tumor suppressor that can be found in the 13q region of DNA is called BRCA2. Mutations in BRCA2, according to the Genetics Home Reference, can lead to patients having a greatly increased risk of developing breast cancer. A 2001 article in Breast Cancer Research, titled "More Breast Cancer Genes?" found that there may be other important tumor suppressors in the 13q region as well. These unknown genes have been termed BRCAX.
13q Genetic Testing
Genetic tests can be used to identify certain deletions in the 13q regions of the genome, according to the National Human Genome Research Institute. These tests can be done to determine whether a patient is at a higher risk for developing breast cancer and may be recommended for patients who have multiple family members with breast cancer. A strong family history of breast cancer often suggests that there is an inheritable genetic mutation that's leading to an increased cancer risk.
Significance
A diagnosis of a deletion in the 13q region of the genome doesn't necessarily mean that a patient will develop breast cancer, merely that she has a higher risk of developing breast cancer in her lifetime. The National Cancer Institute notes that 60 percent of women with a 13q deletion develop breast cancer, compared to the 12 percent of the population that develops it. Men with a 13q deletion can also develop breast cancer and are at a greater risk of developing melanoma, pancreatic and prostate cancers.
