breast cancer

Understanding the Breast Cancer Gene Breakthrough

October 07, 2009 05:30 PM
by Haley A. Lovett
Everyone has gene NRG1, but in many breast cancer cells the gene is “broken.” How will the newfound link between the gene and cancer change the future of medicine?

What Do We Know About Breast Cancer Gene NRG1?

In a study published in the journal Oncogene, British scientists say they’ve found a correlation between the gene NRG1 and breast cancer. Scientists have known that part of chromosome 8 is lost in many cancers, so they’ve searched that missing area for genes that might have tumor-suppressing qualities. NRG1 was in the right location on chromosome 8, and the recent findings indicate that NRG1 may act as a tumor suppressant, leading scientists to conclude that mutations to the NRG1 gene may play a role in the development of breast and other cancers.

Rebecca Smith of the Telegraph describes how NRG1 acts as a “brake, stopping cancer cells from growing,” and that when the gene is damaged, tumors can form. The Press Association notes that in addition to playing a part in half of the breast cancer cases studied, the NRG1 gene may also contribute to bowel, prostate, ovarian and bladder cancers.

The Web site NHS Choices maintains that although some are calling this the greatest cancer breakthrough in decades, it will take lots of time and additional study before scientists will know how NRG1 may work in other cancers and what treatments may come from the discovery.

What Role Do Genes Play in Cancer?

Cancer occurs when abnormal cells divide at a very high rate and grow a tumor. According to NHS Choices, there are two ways that genes can affect cancer. One way is that a gene regulating cell division will become damaged and make the cell divide too quickly. Another is that a gene meant to stop a cell from dividing too much will stop working, and cells will multiply and form tumors.

The cells go haywire because of genetic mutations—changes to the normal genetic makeup of the cells that prevent them from functioning properly.

Genetic mutations can be inherited from parents, or they can develop in certain cell groups during a person’s lifetime, known as somatic mutations. According to the National Library of Medicine, the most common causes of cancer are somatic mutations.

The changes to the NRG1 gene that could contribute to cancer are thought to be somatic mutations. But there are some inherited genetic mutations that are thought to contribute to breast cancer as well. Mutations to BRCA1 and BRCA2 are known hereditary factors in the development of breast cancer.

What Does the Discovery of This Cancer Gene Mean for Cancer Treatment?

Identifying the cause of cancers is becoming increasingly important for treatment. If researchers can better understand what went wrong to cause a particular cancer, they are better able to develop therapies to stop the cancer from spreading.

Recently, scientists studied how different drug therapies affect various genes. According to David Rose of The Times of London, cancers may one day be treated according to the genetic mutation causing the cancer, rather than the cancer’s location in the body. 

Gene therapy may also play a larger role in fighting cancer, as more cancer-causing genes are identified. Gene therapy, the National Cancer Institute reports, works to alter a person’s genetic makeup to stop disease, either targeting cancer cells to destroy, or making healthy cells more resistant to cancer. Gene therapy is currently still in an experimental phase.

Is Genetic Testing for Hereditary Cancer-Causing Gene Mutations Worthwhile?

The tumor suppressing genes BRCA1 and BRCA2 are at the heart of any debate over breast cancer risk and genetic testing. But according to Aetna InteliHealth, abnormal BRCA1 and BRCA2 genes only make up about 3 percent of all breast cancers; the National Cancer Institute puts them at 5 to 10 percent, and states that women with altered BRCA genes are about 5 times more likely than other women to develop breast cancer in their lifetime. Knowledge of the hereditary mutation may result in close monitoring and early detection if breast cancer does develop.

Genetic testing cannot tell a person whether they will develop cancer in their lifetime, but it can provide clues about their level of risk.

BRCA tests currently cost thousands of dollars, but the genetic tests may become more affordable in the future.

One concern for people considering genetic screening is that the test results will become a part of that person’s medical history and may not stay private. According to the National Cancer Institute, several laws aim to protect a person’s medical privacy, including the Health Information Portability and Accountability Act (HIPAA), which aims to prevent the unwanted release of a patient’s medical records.  

The 2008 Genetic Information Nondiscrimination Act (GINA) prevents health insurance providers and employers from discriminating against people based on genetic information. GINA, however, does not cover life insurance, disability insurance or long-term care insurance, and genetic information may be used to determine a person’s eligibility for those types of insurance.

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