Breast Cancer Essay -- Diseases Medical Medicine Essays

Breast Cancer Chromosome 17 and BRCA1 Among the most common diseases affecting the female population, breast cancer develops in one of every eight American women. This means that almost 200,000 women suffer from the disease each year. Doctors would advise women to take necessary precautions, such as routine surveillance, in order to ensure a life without obtaining this disease prior to understanding any genetic linkage of breast cancer. Although many external factors contribute to breast cancer, current investigations reveal that five to ten percent of these cases may be attributed to genetic inheritance (Lynch, 1999). This knowledge, an ingenious finding by Mary-Claire King in 1990, linked breast cancer to the long-arm of chromosome 17 (Biesecker, 1997). Since the discovery of possible genetic linkage, doctors have been able to delineate those individuals who are most prone to the disorder, and immediately, these women begin to act in accordance with doctor’s suggestions to reduce their risk (Rosenthal et. al., 1 999). Mary-Claire King not only determined that breast cancer was a genetic disorder, her findings also suggest that the mutation of gene BRCA1 (Breast Cancer one) is responsible for most inherited breast cancer. Further investigations pointed to another gene, BRCA2, as also contributing to genetic inheritance. Unlike BRCA1, BRCA2 is found on chromosome 13. Researchers have found that 90% of all inherited cases of breast cancer may be due to mutations of these individual genes (Lynch et. al., 1999). The BRCA1 gene has the locus designation, 17q21, and is responsible for this autosomal dominant syndrome (Merajver et. al., 1995). This tumor suppressor gene, contains 23 exons, each ranging from 41 to 311 bas... ...counseling in hereditary breast cancer. Cancer Genet. Cytogenet 1999(109): 91-98. Merajver, S.D., Frank, T.S., Xu, J, et. al. Germline BRCA1 mutations and loss of the wild-type allele in tumors from families with early onset breast and ovarian cancer. Clin. Can. Res. May 1995 (1): 539-544. Miki, Y., Swensen, J., Shattuck-Eidens, D., et. al. A strong candidate for the breast and ovarian cancer susceptibility gene BRCA1. Science. Oct. 1994(266): 66-71. Puget, N., Stoppa-Lyonnet, D., Sinilnikova, OM., Pages, S., Lynch, HT., Lenoir, G.M. and Mazoyer, S. Screening for germ-line rearrangements and regulatory mutations in BRCA1 led to the identification of four new deletions. Cancer Research. Jan. 15, 1999 (59): 455-461. Rosenthal, T.C., and Puck, Stirling M. Screening for genetic risk of breast cancer. American Family Physician. Jan 1999 (59): 99-104.