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Jennifer Masciovecchio
Dean Grosovsky
Pre-Med A
Final Paper
13 May 2014
BRCA 1 and BRCA 2
In recent news, Angelina Jolie made the bold to move to get a double mastectomy. This
is because it had been determined that she carried the mutated form of the genes that can cause a
higher risk in developing breast cancer. Because she had the mutated form of the gene, Jolie had
an 87% chance of developing breast cancer. Her bold move raised awareness to the public about
the mutated forms of the genes and made people start to question their own, personal risk of
developing cancer. This raises many questions for people such as what is the probability of
someone developing cancer if they inherit the mutated form of the genes? What is the risk for
men who inherit the gene? Are there any other options besides a double mastectomy? The
reasoning behind the in-depth analysis of this topic is that anyone could be carrying this gene and
it is important to know the probability of developing cancer if the gene is being carried.
The major cause of this high risk in developing cancer is due to a gene known as BRCA
1. The official name of BRCA1 gene is breast cancer 1. It belongs to the class of genes known as
tumor suppressor genes. This gene helps prevent cells from rapid growth and division in an
uncontrolled way. BRCA 1 protein also regulates the activity of other genes and plays a very
important role in embryonic development. BRCA1 is located in the arm of chromosome 17 at
position 21. It is located from base pair 41,196,311 to base pair 41,277,499 on chromosome 17.
BRCA1 and BRCA 2 (a gene similar to BRCA 1) are human genes that produce tumor
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suppressor proteins. The main function of these proteins is to help repair damaged DNA.
Therefore, it plays a huge role in ensuring the stability of the cell's genetic material. When either
of these genes is mutated, or altered, such that the protein is not produced then the repairing of
damaged DNA may not take place properly. This causes the cells to divide rapidly or
uncontrollably which can allow them to develop more genetic alterations that can lead to cancer.
Women who inherit a mutated copy of the BRCA1 gene collect broken and deformed
chromosomes. It highly increases the risk of accumulating mutations that will lead to rapid cell
growth and cancer. Men who inherit the defective genes are also more likely to develop breast or
prostate cancer. The mutated BRCA1 genes are inherited in an autosomal dominant pattern;
therefore a child only needs to inherit one copy of the mutated gene to increase the risk of
cancer. Children with a parent having a BRCA1 mutation have 50% chance of inheriting the
mutation.
People inheriting the defective gene might not develop cancer but inheritance greatly
increases the risk. Out of every 100 women who inherit a mutated gene, as many as 60 will
develop breast cancer by age 50. By age 70, approximately 80 people will develop breast cancer.
Men with BRCA1 mutation have an approximately 2% to 3% chance of developing breast
cancer by the age of 70. About 80% of women who inherit a harmful BRCA1 mutation will
develop cancer by the age of 70. Besides breast cancer, BRCA1 mutation also increases women's
risk of developing Fallopian Tube cancer, Ovarian cancer and Peritoneal cancer. Both men and
women with BRCA1 mutation may also have high risks of pancreatic cancer. Men who inherit
the mutated form of BRCA1 develop an increased risk of several types of cancers such as breast,
skin and prostate cancer. Men do have a lower risk for developing cancer then women who carry
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BRCA1. They have an approximately 2% to 3% chance of developing breast cancer by the age
of 70. Men have a much lower risk of developing breast cancer then women because their breast
duct cells are less developed than women and because they have lower levels of female
hormones that affect the growth of breast cells. The risk of inheriting BRCA1 is not 100% in
men but there is still an increased chance of developing cancer.
Although the risk of developing cancer is increased, there are many preventative
measures a person can take if they carry the mutated gene. It has been found that the
prophylactic double mastectomies have been the most successful treatment and prevention of
breast cancer. Patients can also opt to have just a portion of the breast tissue removed. Also a
prophylactic salpingo oophorectomy (the removal of ovaries and fallopian tubes) has proven to
greatly decrease women's risks of developing ovarian cancer with the mutated gene from 11% to
3%. However, Angelina Jolie had 87% chance of getting breast cancer through this mutation,
but for others that percentage might be a lot different. If a person’s risk factor is in the low 3040% than a double mastectomy might be reconsidered.
However, many of times the report that records a person’s chance of developing cancer
from the mutated gene can be inaccurate. So, the chances of developing breast cancer aren't
always necessarily as high as the reports have shown. This may be taken into consideration when
deciding what preventative measures to take.
For people who have a family history of breast cancer, they should undergo "active
Surveillance" for breast cancer. This means that they have to get a mammogram and MRI check
up every six months to a year starting at the age of 25. The earlier breast cancer is detected the
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better the chance of successfully treating it. It is definitely important to take preventative
measures long before a problem has even occurred. Studies have shown that MRI may be less
specific and could lead to more false-positive results. Also, it can only screen certain types of
breast cancer; it has been found to be more sensitive than a mammogram. Men with BRCA 1 or
2 mutations should also get regular screening as well as testing for prostate cancer.
New studies showed that medication such as Tamoxifen and Raloxifene, which are
medications that act as estrogen blockers, can reduce the risk of breast cancer by 40% to 50%
especially if you carry the mutated genes. However, this drug can increase the risk of blood clots
and uterine cancer. Further testing is needed in identifying the benefit and harm of using this
drug. It is encouraged that women at high risk should limit their consumption of alcohol, eat a
low-fat diet, engage in regular exercise, and avoid menopausal hormone use. These lifestyle
recommendations do not have enough data collected to completely support their effectiveness,
but it has shown in most situations to reduce the over-all risk of developing cancer.
All in all, Women and Men have an increased risk of developing cancer if they display
the mutated form of the BRCA1 or BRCA2 genes. Most women have a 60-80% chance of
developing breast cancer while men have a 2-3% of developing it with carrying the mutations.
The Mutated BRCA genes also increase the risk of Prostate cancer in men and Ovarian cancer,
Fallopian Tube cancer, and Peritoneal cancer in women. However, regular screenings and
consistent checkups and more drastic measures such as prophylactic surgeries and chemotherapy
prevention can help decrease the risks of developing cancer. Unfortunately, there is no definite
way to completely prevent or cure cancer. The more radical surgeries such as the mastectomy
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and the oophorectomy have worked as great reduction factors for developing cancer for people
who carry the gene. The oophorectomy decreases chances of dying of Ovarian cancer by 80%
and the double mastectomy decreases chance of death from Breast cancer by 50%.