Today I want to talk about cancer. That vicious disease that takes our mothers, our daughters, sisters, friends, grandmothers, boobies, uteri, and all our menfolk as well.
Little is known about the genes behind cancer by the public, unless you are one of those fortunate few to be able to be diagnosed with it, in which case, PLEASE make sure your relatives are tested as well.
I will be giving you all facts as I know them, as well as my references for those facts, so you can decide for yourselves.
First a brief history on these two terrible genes, BRCA1 and BRCA2.
Please note that the following is taken from http://www.cancer.gov/cancertopics/factsheet/risk/brca
After reading all that is below, please take a moment and ask yourself, if you were to be tested positive for this gene, wouldn't you want a second opinion?
The above link is a story about a woman who tried to get a second opinion and couldn't because some COMPANY has patented the gene. If you are one of these positive-tested people, please look into this more. Hopefully we can help the fight against this. This is going to end up being a landmark case, because of the way it blends medicine, patent law, breast cancer activism, and civil liberties. If this blog is a little confusing (I know I can be) let me know. Please pass this along to your friends as well.
- What are BRCA1 and BRCA2?
- How do alterations in BRCA1 and BRCA2 affect a person's risk of cancer?
Each year, more than 192,000 American women learn they have breast cancer. Approximately 5 to 10 percent of these women have a hereditary form of the disease. Changes, called alterations or mutations, in certain genes make some women more susceptible to developing breast and other types of cancer. Inherited alterations in the genes called BRCA1 and BRCA2 (short for breast cancer 1 and breast cancer 2) are involved in many cases of hereditary breast and ovarian cancer. Researchers are searching for other genes that may also increase a woman's cancer risk.
The likelihood that breast and/or ovarian cancer is associated with BRCA1 or BRCA2 is highest in families with a history of multiple cases of breast cancer, cases of both breast and ovarian cancer, one or more family members with two primary cancers (original tumors at different sites), or an Ashkenazi (Eastern European) Jewish background. However, not every woman in such families carries an alteration in BRCA1 or BRCA2, and not every cancer in such families is linked to alterations in these genes.
A woman's lifetime chance of developing breast and/or ovarian cancer is greatly increased if she inherits an altered BRCA1 or BRCA2 gene. Women with an inherited alteration in one of these genes have an increased risk of developing these cancers at a young age (before menopause), and often have multiple close family members with the disease. These women may also have an increased chance of developing colon cancer.
Men with an altered BRCA1 or BRCA2 gene also have an increased risk of breast cancer (primarily if the alteration is in BRCA2), and possibly prostate cancer. Alterations in the BRCA2 gene have also been associated with an increased risk of lymphoma, melanoma, and cancers of the pancreas, gallbladder, bile duct, and stomach in some men and women.
According to estimates of lifetime risk, about 13.2 percent (132 out of 1,000 individuals) of women in the general population will develop breast cancer, compared with estimates of 36 to 85 percent (360-850 out of 1,000) of women with an altered BRCA1 or BRCA2 gene. In other words, women with an altered BRCA1 or BRCA2 gene are 3 to 7 times more likely to develop breast cancer than women without alterations in those genes. Lifetime risk estimates of ovarian cancer for women in the general population indicate that 1.7 percent (17 out of 1,000) will get ovarian cancer, compared with 16 to 60 percent (160-600 out of 1,000) of women with altered BRCA1 or BRCA2 genes. No data are available from long-term studies of the general population comparing the cancer risk in women who have a BRCA1 or BRCA2 alteration with women who do not have an alteration in these genes. Therefore, these figures are estimated ranges that may change as more research data are added.
Some evidence suggests that there are slight differences in patterns of cancer between people with BRCA1 alterations and people with BRCA2 alterations, and even between people with different alterations in the same gene. For example, one study found that alterations in a certain part of the BRCA2 gene were associated with a higher risk for ovarian cancer in women, and a lower risk for prostate cancer in men, than alterations in other areas of BRCA2.
Most research related to BRCA1 and BRCA2 has been done on large families with many affected individuals. Estimates of breast and ovarian cancer risk associated with BRCA1 and BRCA2 alterations have been calculated from studies of these families. Because family members share a proportion of their genes and, often, their environment, it is possible that the large number of cancer cases seen in these families may be partly due to other genetic or environmental factors. Therefore, risk estimates that are based on families with many affected members may not accurately reflect the levels of risk in the general population.