Introduction
Breast cancer is a type of disease where certain breast cells develop abnormally mostly in the milk ducts and lobules leading to formation of tumors. The exact cause of breast cancer is a topic that has flavored many debates and researches but still remains unknown. However a plethora of research has established that certain risk factors have a direct linkage with breast cancer. Breast cancer related risk factors are wide and varied and may include lifestyle choices like smoking/ diet or factors that are beyond the control of a person like gender, age or family history. It is however worth noting from the start that the presence of a risk factor does not essentially mean one will contract breast cancer. The existence of breast cancer in certain families raises the question; do genetics play a role in breast cancer? Scientists have established that inherited breast cancer is mostly associated with two common abnormal genes BRCA1 and BRCA2 (Slowik, 2011). This paper will examine various aspects of breast cancer with a primary reason to establish whether genetics play a role in breast cancer. The report will first examine the background information on breast cancer including the etiology, the pathophysiology, the diagnosis and treatment. The paper will also evaluate and summarize two journals addressing the role of genetics in breast cancer as well as the way the media presents these subject to the public.
Background Information on Breast Cancer
Breast cancer is a malignant swelling (tumor) that could affect one or more parts of the breast tissue. The most commonly affected parts are the lobules that generate milk and supply to the ducts and the lining within the milk ducts. Suffice to say that breast cancer not only affects humans alone but other mammals as well and contrary to popular belief breast cancer also affects men but affects women in most cases. It is the most common invasive cancer affecting women in the world contributing to 16% of all cancers in women. It is more common in the USA, where it affects up to 120 out of 100,000, than in any other country.
There is no known cause of breast cancer but several factors can predispose someone to breast cancer. The said risk factors include genetic predisposition, age, female gender, high hormone levels, bareness or lack of breastfeeding, iodine deficiency, economic status and race. Incidences of Breast cancer appear to be higher among people with higher incomes probably due to their lifestyle or over-diagnosis as result of access to better health services. Smocking of tobacco especially too much and at an earlier age is another risk factor. Other risk factors include obesity, diet with high fat diet, exposure to radiation, disruptors of the endocrine system, alcoholism, family history of breast cancer and shift work Mutations of certain genes seem to be a predisposing factor.
Cancers, including breast cancer, are as a result of interaction of environmental factors and defective genes (mutations). Certain genes are responsible for the regulation of cell division and when these genes are defective cells divide indefinitely resulting in cancer. Mutations in the genes coding for the proteins responsible for correcting DNA errors can also cause cancer. These mutations may occur at birth or be inherited. Mutations of the second class of genes often results in other mutations leading to unregulated growth, lack of attachment and spread of the cancerous. Another pathway responsible for breast cancer as well as other cancers is the mutation of genes responsible for the programed cell death (apoptosis) resulting in cells failing to “committing suicide” at the end of their functional life. As a result the cells accumulate since there is no clearance. Mutations that results in breast cancer have been associated with exposure to estrogen hence the higher incidence in females. The documented Mutations that increase the risk for breast cancer include: BRCA1, BRCA2, TP53, STK11, PTEN, CDH, CHEK2, ATM, PALB2, BARD1, BRI, FGFR2, RAD51 TP53, NF1 or NBN, PALB2, BRIP1, RAD50, 2q35, TGFB1, LSP1, TOX3, MAP3K1 and 8q. Some of the mutations also cause other rare syndromes so that the very presence of the syndromes could imply an increased risk in breast cancer. Suffice to say that the interactions of these mutations and the other risk factors have not been established. However it is definite that the genetic factors play a significant role in increasing the risk of breast cancer. It is important to note that only half of the familial breast cancer has been explained at the level of genetic predisposition.
Breast is characterized by a lump in the breast that is inconsistent with the rest of the tissue. Other symptoms of breast of breast cancer include lumps in the armpits, inversion of the nipple, pain, swelling of the nipple, itching, redness of the breast and increased sensitivity. Other non-specific symptoms may include fever, joint pains, jaundice, discharge in the nipple and weight loss. The presence of a lump in the breast is usually the first diagnosis but there are several diagnostic tools which include mammography, MRI, ultrasound and biopsy. Biopsy is the most accurate and definitive diagnostic tool but it is invasive thus is only employed when the results from the other techniques are not definitive enough.
The treatment of breast cancer depends on the stage, size, rate of proliferation and other tumor characteristic. Treatment is often multidisciplinary involving surgery, radiation, chemotherapy and immunotherapy. Surgery involves the extraction of cancerous cells and other cells and surrounding tissues and may be the removal of the entire breast (mastectomy), a quarter of it (quadrantectomy), or just the lump (lumpectomy) depending on the stage, size and rate of growth of the lump. The medication include hormone blocking drugs e.g. tamoxifen, anastrozole, letrozole and monoclonal antibodies e.g. trastuzumab. Radiotherapy may be in form of internal radiation (brachytherapy) or external therapy on the affected region often after surgery.
Annotated Bibliography
1. Beggs, A. D., & Hodgson, S. V. (2009). Breast cancer susceptibility genes analysed into three groups (Genomics and breast cancer: the different levels of inherited susceptibility). European Journal of Human Genetics, 17, 855–856.
The authors categorises the genetic mutations predisposing people to Breast cancer into three classes: the highly penetrant genes, the intermediate penetrance breast cancer susceptibility genes and the low-penetrance breast cancer susceptibility genes. The first class of mutations is fairly rare and includes mutations in genes BRCA1, BRCA2, TP53, STK11, PTEN and CDH1. There are genetic screening tests available for these mutations and appropriate measures including counseling can be put in place. The second category confers an intermediate increase in the risk and includes mutation in CHEK2, ATM, PALB2, BARD1, and BRIP. According to the authors these genes belong to the same pathways involved in DNA repairs and don’t increase risk in women with BRCA1and 2. For mutation there is no screening test because they are very rare and investing in screening test is considered financially imprudent. The third and final class of mutations is very common but confers very low risk of breast cancer. These mutations have been widely studied a lot of literature on the mutations exist and are mainly on the FGFR2 and RAD51 gene.
The authors clearly state that the role of these mutations in the mechanism and pathogenicity of breast cancer. They also state that there are possibly many more mutations involved in breast cancer predisposition especially the low penetrance susceptibility. The low penetrance susceptibility mutations are of great interest to companies developing screening tests. It is not clear how much is understood on the impact of these tests. The authors also assert that due to the dynamic knowledge on the genetic factors in breast cancer the best susceptibility screening test can’t be easily determined. They conclude that despite the growing knowledge on the genetic factors involved in breast cancer the other risk factors such as age, menopause, smoking, hormone contraceptive, child bearing, hormone replacement therapy and breast cancer are vital in the development of breast cancer and must not be underrated. According to the authors full understanding of all the predisposing factors, genetic and environmental, would have a great impact on counseling. This paper will be useful in identifying the predisposing mutations and other factors.
2. Ripperger, T., Gadzicki, D., Meindl, A., & Schlegelberger, B. (2009). Breast cancer susceptibility: current knowledge and implications for genetic counselling. European Journal of Human Genetics, 17, 722–731.
The authors outline the genes and single nucleotide polymorphisms (SNPs) that have recently been associated with increased susceptibility to breast cancer. According to the authors enormous evidence linking increased breast cancer susceptibility to mutations on TP53, CDH1, PTEN, STK11, NF1 or NBN which also cause certain rare syndromes. Mutations on genes such as CHEK2, ATM, PALB2, BRIP1 and RAD50 which are in the DNA repair pathway have also been found to moderately increase susceptibility to breast cancer. Some low-penetrance breast cancer SNPs at the genetic and chromosomal level with no functional genes that include FGFR2, 2q35, TGFB1, LSP1, TOX3, MAP3K1 and 8q have also been identified. These latter categories of susceptibility SNPs also modify the high risk BRCA1/BRCA2 mutations. The authors also outlined the possible benefit of the recent developments in prevention and therapy as well as the shortcomings of the genetic screening for mutations linked with intermediate and low increase in breast cancer vulnerability.
According to the authors the most common mutations that increase the risk of breast cancer occur on BRCA1 or BRCA2 and account 20 to 40% of all the hereditary breast cancer and less than 5% of all breast cancer cases increasing the risk for breast cancer by 60-85% and also increase the risk for ovarian cancer. According to the authors the fact that the risk for breast cancer is based on the interaction of many factors both genetic and environmental makes it difficult to calculate the cumulative risk as well as to design models of predicting risk that integrate the various genetic variations. This limits the clinical use of the knowledge in susceptibility mutations. The other challenge is that half the genetic predisposition to hereditary breast cancer is yet to be explained. However with the increase characterization of the genes involved and advancing technology the knowledge may prove useful in the near future.
How the Media conveys the Role of Genetics in Breast Cancer to the Public
It is undeniable that the media has an immense role in the public understanding of health issues and more so of issues like the relationship between genetics and breast cancer. In a wide array of media sources, breast cancer has wide media coverage more so in the face of increased advocacy on breast cancer. Every day human beings across global boundaries are exposed to a host of breast cancer related messages from scores of media including television, media, magazines, editorial content, movies, direct social marketing, internet and all types of advertising. In the sound bite culture of today, the media is the major source of information on the relationship between genetics and breast cancer. The media is therefore hugely responsible for the public’s understanding of the above mentioned relationship.
The media presents the issue of genetics and breast cancer through diverse varied ways all which are aimed at understanding the phenomenon. Few people experience firsthand a critical disease; most don’t know what it is like to be suffering from a terminal disease like breast cancer. The reality of such a disease and our responses to it is experienced vicariously through the power of the pen created by journalists and the audio visual reality of radio/television reports. The public perceptions of the role of genetics in breast cancer are therefore heavily reliant on the media’s portrayal of the issue. The reliability of the facts which translates to correct interpretation also relies on the form of media and how the message is conveyed. It has been documented that on basis of biased sensual portrayal of messages, women have been known to perceive genetics as the highest risk factor with disregard to other breast cancer risk factors (Herderson & Kitzinger, 1999).
This could be due to the form of media and the content of the message. Take the internet for example, it is one of the most accessible, cheap, widespread and fast modes of conveying messages on the subject matter. But regardless of the host of reliable websites, the internet is generally not a regulated media source which can lead to inaccuracies that result in wrong perceptions. Human interest stories in contrast to fact based health messages have often been favored in many print forms like women magazines. Print media like brochures or books have the advantage of loyal readership and can pass the message to a lot of people. However print media often requires a lot of lead time (Jones, 2004). The television on its part has visual appeal and the advantage of simulation useful in explaining the whole subject of genes and breast cancer. The nature and complexity of the message to the common public however requires understanding derived from repetition which the television and its temporary exposure may fail to cover (Zimmerman, 2004, P. 88). The list of media forms that convey breast cancer messages and its relationship to genetics may be inexhaustible but one thing is clear; media coverage of breast cancer genetics varies according to the type of media and the message conveyed. It can however be ascertained that the media presents the subject of breast cancer genetics either as ‘hard’ fact based messages or ‘soft’ human interest stories (Herderson & Kitzinger, 1999).
In conclusion breast cancer results from an interaction of genetic, environmental and lifestyle factors. The genetic factors have been widely studied and are very important because they seem to be at the very heart of the pathogenesis of breast cancer. It is clear that cancer can only occur if there is an alteration at the genetic level thus the other factors could play a role in causing the genetic alteration. The growing body of knowledge on the role of genetics could prove useful in designing screening tests for predicting the risk of breast cancer.
References
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