Wednesday, August 22, 2012

How BRCA1 and BRCA2 Genes Relate To Breast and Ovarian Cancers

(Image form: The BRCA1 network)

Breast cancer research has led to the identification of two genes that, when functioning properly, regulate cellular growth and prevent the runaway metastasis of mammary tissue which leads to breast tumors and ultimately cancer. These genes are, with typical scientific economy, called BRCA1 and BRCA2. Because of the unusually repetitive nature of these genes, speculation that they function as "regulator" genes seems well-founded, and the link between abnormalities in these genes and breast cancer has already been established. The mystifying part is understanding why these genes malfunction, and if so, what can be done about it to prevent at-risk or genetically predisposed women from developing breast cancer.


One question researchers at Oxford pose is why these genes, which seem to be universally expressed, seem to be so intrinsically tied to breast and ovarian cancer? Cancer researchers believe that finding the answer to this question may lead to new, non-invasive therapies and perhaps even prophylactic treatments for women whose genetic code reveals a predisposition toward these types of cancers. If they can work out how the breakdown of these genes relates to specific types of cancer, the ramifications for diagnosis and treatment of other forms of cancer are potentially unlimited.

A second question is whether the "masking" of these gene expression in the human body may be a contributing factor in leading to cancer, or if genetic derangement or disarray might be the culprit. Until the mechanisms by which these genes govern cellular development are understood, this remains the more daunting question, as it is the basis for everything discussed in the first. Without a clear understanding of how these genes regulate cellular activity and what specific mutations or anomalies within them cause them to cease working properly, a solution to the myriad riddles cancer poses becomes impractical at best and science fiction at worst.

What is known about BRCA1 and BRCA2 is that the anomalous functions, also known as mutations, which appear to be the proximal cause of breast and ovarian cancer are hereditary. Both of these genes, when present in their mutated states in women who are susceptible to breast cancer as a result of heredity, give a lifetime risk of breast cancer approaching eighty percent. The difference is that in BRCA1-mutated women, the disease appears to have an earlier lifetime onset than in BRCA2-mutated women.


It should be borne in mind that males also carry these genes, and male breast cancer, while rarer than female breast cancer, is still certainly possible. In males carrying mutated BRCA1 genes, the risk of prostate cancer appears to be vastly elevated, whereas the BRCA2 gene can be at least theoretically linked to pancreatic, prostate or ovarian, stomach, and skin cancer in both men and women. By understanding the mechanics and mechanisms of these genes, how they express themselves in regulating cellular growth, and what mechanisms cause them to stop working, it is entirely possible that these two genes may help us unlock the secret of one of modern man's greatest threats to life and longevity.


In laboratory experiments, scientists have determined that BRCA1 plays a critical role in repairing damage to double-strand DNA at the sub-genomic level, beginning to interact with and repair the damaged portions of the DNA within minutes of the initial damage. This makes BRCA1 first on the scene by a matter of hours before other proteins and genes begin their own work. Scientists theorize this cellular healing mechanism works by altering the chromatin structure of the cellular nucleus to allow other repair proteins into the nucleotides.

While this exciting discovery is not a cure in itself, it does offer hope that we are finally making strides toward understanding the role that BRCA1 and BRCA2 play in hereditary cancer and perhaps finding new ways of treating various cancers. Since the roles of BRCA1 and BRCA2 in cellular healing are so evident, it stands to reason that these genes may lack an "off switch" in their mutated form. By studying and understanding the mechanics of these genes, it is possible we will be able to determine how to both predict and preempt the onslaught of numerous types of cancer. If so, this discovery offers hope we might finally eradicate cancer altogether.

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