Hereditary Breast Cancer: The Implications of Genetic Mutations

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Hereditary Breast Cancer:
The Implications of Genetic Mutations
Nicole Kownacki
Felician College

Abstract
The purpose of this paper is to examine the role genetics play related to hereditary breast cancer and the options available for risk reduction and prevention. Four published articles, two medical databases and a genetic focused website were examined during the process of this research. Breast cancer is one of the leading causes of death amongst women and heredity is second only to age amongst risk factors. This paper will show how genetic mutations are linked to hereditary breast cancer and the degree of risk they pose on carriers of these mutations. This paper will also examine the process by which affected individuals should be tested for the mutations, who should be tested and options available for cancer prevention and early detection are available. General statistics regarding the mutations, various preventative actions and screening methods will also be disclosed throughout the course of the paper.

Hereditary Breast Cancer:
The Implications of Genetic Mutations
Documented awareness of breast cancer dates back as far as 1600 BC in Egyptian writings. The idea that breast cancer is linked to heredity was first looked at in the late 1800’s. In 1866 a famous French surgeon by the name of Paul Broca came out with the “Broca” report showing that breast cancer can be inherited through families passing from one generation to another (Van der Groep, Van der Wall, & Van Diest, 2011, sec. B). He identified this by constructing a pedigree of his wife’s family after she was diagnosed with breast cancer. Presently, a family history of breast cancer is one of the highest risks for developing breast cancer, second only to age. The purpose of this paper is to examine the role genetics play related to hereditary breast cancer and the options available for risk reduction and prevention.

Women with a family history of breast cancer have a significant twofold higher lifetime risk of developing breast cancer than those who do not. Although genetic mutation is a definite factor amongst familial breast cancer, it is not the only link since there are families with breast cancers without germline mutations. According to Isaacs, Fletcher, & Peshkin (2011), “familial cancers may be associated with chance clustering of sporadic cancer cases within families, genetic variation in lower penetrance genes, a shared environment, or a combination of these factors” (sec. 3). The majority of hereditary breast cancers are linked to two genes, BRCA1 and BRCA2. These genes were first discovered in in 1994 and 1995 respectively and pose a risk of developing breast cancer in women up to 87% by the age of 70 if they carry a mutation in either one of these genes (Metcalf et al., 2007, p. 208). Men who have an abnormal BRCA2 gene are approximately 80 times more likely to develop breast cancer than men who don’t, which is about 8% by age 80 ("Genetics," 2012, sec. 2). Hereditary genetic mutations account for approximately 10% of all breast cancer, most commonly being BRCA1 and BRCA2 mutations.

What are BRCA1 and BRCA2 genes and who has them? BRCA1 and BRCA2 are tumor suppressor genes and everyone has them. Since they are tumor suppressor genes they play an important role in maintaining gene integrity, they repair damaged DNA, and serve as checkpoints in cell cycles which allows for repairs to be made before mitosis occurs (Isaacs et al., 2011). The problem and the increased risk for cancer occur when there is a mutation in one or both of these genes. Isaacs et al., (2011) said the following: Germ line mutations in BRCA1 and BRCA2 result in mutation carriers having loss of one of their wild type alleles and thus they have only one rather than two functional alleles of these genes in their cells. This leads to an increase in genomic instability and tumorigenesis. Tumors in carriers tend to demonstrate loss of the other wild...
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