Breast Cancer Risk Could Depend on a Combination of Gene Variation and Environment

A recent topic for many people concerned about breast cancer is the genetic factors involved. Genetics is a confusing topic for many people because it can be hard to determine the exact risk of getting a disease. While we know that genetics is a factor, the specific genes that cause cancer have been discussed. 

Genetic factors

Genes are the instructions for the body, passed down from the mother and father. When these genes mutate, it can have negative consequences. About five to ten percent of breast cancers are caused by gene mutations.

For breast cancer, the BRCA 1 and BRCA 2 are the genes that are most commonly connected to the disease. Everyone has these genes in their genetic code. However, only some people get the inherited mutation. Both parents can pass down the mutated gene. Therefore, the risk exists for men, as well as women. Fortunately, these mutations are rare. It depends on your ethnicity and a myriad of other factors. For example, in Ashkenazi Jewish women, there is about an eight to ten percent chance of carrying the gene mutation. By contrast, African American women have a one percent chance of getting the mutation. So, there are great variances among different populations. If you are a part of a community with increased risk, you may want to consider preventative measures and genetic testing.

How does the mutation cause cancer? Most breast cancers are caused by triple negative factors. Hormone receptors, like the estrogen receptor-negative and the progesterone receptor negative, are not present in triple negative breast cancer. Women with BRCA1 have an increased risk. By contrast, BRCA2 carriers get cancers that are estrogen receptor positive. Having either mutation will increase the risk of a secondary tumor. If that happens, it is likely the tumor will occur in the other breast. Active care can diagnose both conditions. Treatment of both tumors is suggested. As discussed earlier, having the gene is not the only risk factor, but can add to other factors. For example, exercise can decrease the risk. So can breastfeeding. Other factors, like smoking, will increase the risk. Drinking alcohol, radiation, and other exposures are also risk factors. If you have also been predisposed to cancer, you may want to eliminate environmental exposures and make healthy lifestyle choices.

What does it really mean to have the gene?

Does having the gene mean you will get breast cancer? Not exactly. There is no one hundred percent chance that you will receive cancer. The risk increases as you age. Depending on the mutation, your chances of getting the disease are about forty-five to sixty-five percent by age seventy. Contrast that with the eight percent chance a woman without the mutation has for developing the disease. These numbers are the average risk, so everyone might be slightly different. Other factors, like exposure to environmental factors, exist. However, if you have one of the mutations, the increased risk can be concerning. When breast cancer is discussed, most people think of women. It should be noted that men are also at risk for this disease. Men have a risk of 65 in 1000 for BRCA2. There might also be a risk for men with BRCA1, but that exact risk has not been determined. For men, having the BRCA2 mutation means a fifteen percent high risk of prostate cancer as well. For women, the BRCA1 gene mutation has a thirty-five to seventy percent chance of ovarian cancer, while BRCA2 causes a ten to thirty percent chance of ovarian cancer. These genes may also be linked to pancreatic cancer as well.

Preventative measures for breast cancer are a topic of great discussion, including for those with gene mutations. To make the correct determinations for you, there is genetic testing. Genetic testing is widely available and is an option that should be discussed with your doctor. It is most necessary for people with familial risk for the gene mutations, those forty-five or younger who have had breast cancer, other risk factors. For genetic testing to be most effective, it is done on the person with the cancer history first. If that person does not have the gene, there is no more need for genetic testing. If the gene is found, the next test will be given to family members who could have inherited the gene. This testing is pretty simple, as you will just need a blood test. Talk about any results with your genetic counselor and doctor. It is perfectly normal to have many questions about the process and results. Also, be mentally prepared if the results come back positive. Talk to a support group or therapist if needed.

Clinical exams are an easy preventative measure. Check your breasts monthly for lumps and other abnormalities. If you require further evaluation, see your doctor. They may suggest a mammogram. People with the gene mutation may want to get screened more regularly than the general population.

If you have the gene, you may consider more invasive preventative measures. There are a few medications known to lower the risk. These drugs are called tamoxifen and raloxifene. Their use should be discussed with your doctor. For some, the risk is great enough to undergo surgery. This all depends on personal risk and if you feel a surgical option is necessary. The most common surgical measure is a mastectomy. If you are determined to have cancer, you may want to talk to your doctor about the risks of a mastectomy. There are different types of mastectomies, depending on your needs and risk. Some women will opt for it, but others will decide to forego the procedure. To lower the risk of ovarian cancer, women can have their ovaries removed as well. This also should be considered as a preventative measure.

Conclusion

When it comes to thinking about breast cancer risk, you may want to start by looking at your background and familial history. Understanding the genes and the risk factors is important. If you think you may be at risk, you can undergo clinical assessment and genetic testing. If you are found to have the gene, then you can focus on preventative measures. Know that there are many organizations and resources out there to help you find information, genetic counselors, and doctors. If you haven’t been diagnosed, don’t panic. Even if you do have the gene, there are many factors that contribute to getting cancer. It is not plausible to come up with an exact risk formula for each person. Still, consider if any of the preventative options are right for you. Lifestyle choices are a great place to start. They are non-invasive and cheaper than the other options.

Reference

https://www.cancer.gov/about-cancer/causes-prevention/genetics/brca-fact-sheet