Friday, June 21, 2013

GENETIC CANCER SCREENING

Abstract

Cancer is one of the most common ilnesses in the present day. While some forms of cancers are perceived to run in families that share particular risk factors, others are caused by abnormalities in genes that are passed down from parents to their offspring. In the last ten years medical experts, scholars and scientists involved in the investigative study of cancer have found out that there are a number of inherited genes in the human body that have a propensity to cause the development of certain types of cancers. The concept of hereditary cancer has emerged as a consequence of findings that gene mutations passed down by parents to their children may contribute to the development of different types of cancer.

In spite of the fact that investigative studies on cancer have indicated that inheriting particular gene mutations may increase an individual’s cancer risk factor, it is noteworthy that cancer is not an inherited illness; only the mutated gene that increases cancer risk factor can be inherited. After a brief introduction on how gene mutations increase the cancer risk factor in affected individuals, this paper will analyze the concept of genetic screening as well as the significance of gene mutation on genetic cancer screening. The concept of genetic cancer screening will be deliberated upon in detail followed by the different steps in genetic cancer screening. This will be followed by a discussion of the legal, ethical and social implications of genetic cancer testing. At the end of the paper will be a summative conclusion of the issues discussed and an alphabetical draft of the references cited herein.

1.0.0 Introduction

Cancer illnesses have become so common in the modern American society that a majority of American families have had one or more of their members diagnosed with cancer. Cancer is also one of the most serious illnesses reported in different parts of the world in the present day. Siegel et al (2013, p. 16) purport that an estimated 1.6 million new cases of cancer are reported annually in the United States of America. This figure is not inclusive of the estimated 64,640 incidents of breats carcinoma and 61, 640 cases of melanoma in situ diagnosed annually. In addition to this, Siegel et al (2013, p. 16) estimate that an expected 580,350 Americans will succumb to death this year as a consequence of cancer; this translates to an estimated 1,600 cancer related deaths every year. According to the Cancer Support Community (2011) in the last ten years medical experts and scientists have found out that there are particular inherited factors in the human body that cause the development of different types of cancers for instance ovarian, prostrate, breast and colorectal cancers. Such genetic factors are as a consequence of gene mutations passed down to offspring by their parents (Cancer Support Community, 2011).


Genes exists in body cells in structures known as chromosomes. Chromosomes are found in the nuclues of human body cells and come in two 23 pairs; consequently, humans have a total of 46 chromosomes. One chromosome in every pair is acquired from the father while the other is from the mother. Chromosomes are comprised of numerous genes: these are coded DNA which also exist in twos. Gene mutations in the body of humans occur due to transformations in the DNA substance. Gene mutations impede the normal functioning of genes. The American Cancer Society (2011b, p. 2) defines gene mutations as “changes in the arrangement of the bases that make up a gene”. Transformations in a single base of the thousands that genes are comprised of has the propemsity to bring about major implications in the body of the affected person. Gene mutations may bring about several chages in body cells; some mutations tend to affect the body protein by making it function ineffectively or rendering it ineffective. While some mutations increase the activities of genes and lead to the manufacure of excessive protein, others increase the risk factors for development of diseases such as cancer (American Cancer Society, 2011b, p. 2).


The American Cancer Society (2011a, p. 1) states that gene mutations are very significant in cancer development. This is due to the fact that gene mutations have a propensity to cause excessive growth of cells whose outcome is the development of cancer. Although some gene mutations are inherited from a person’s parent, other are not ineherited. As a matter of fact, only an estimated 5%-10% of all incidences of cancer are believed to be as a resulted of the risk factors caused by inherited genes. In spite of the fact that inheriting gene mutations from one’s parents does not imply that the affected individual will automatically develop cancer, the Cancer Support Community (2011) posits that such inherited gene mutations increase cancer risk factors.


2.0.0 Important Gene Mutations in Genetic Cancer Screening Mutations that are inherited from one’s parents are also referred to as “germline mutations”. Hereditary mutations occur in sperms or ova that are joined together to form foetuses (American Cancer Society, 2011b, p. 2). There are two main genes that play a very significant role in cancer development and related issues; these are the ocnogenes and tumor suppressor genes. The major difference between tumor suppressor genes and ocnogenes is the fact that tumor suppresors cause the development of cancer when they are inactive while ocnogemes cause cancer when the proto-eoncogenes are activated (Palmer et al, 2006). Oncogenes


Oncogenes are described as types of normal genes found in the proto-oncogenes cells that have become mutated. Proto-oncogenes are responsible for determining and regulating the types of cells in the body as well as the manner in which these cells develop and divide (American Cancer Society, 2011b, p. 2). When proto-oncogenes mutate they transform to oncogenes and no longer function normally. Rather, they are permanently activated even when they should not; this causes them to become uncontrollable and consequently cancerous. The American Cancer Society (2011b, p. 4) states that they are a number of cancer syndromes that are the result of inheritated proto-oncogenes mutations. These include multiple endorcrine neoplasoa type 2 (MEN2) which is caused by a mtation of the RET gene. Tumor Suppresor Genes


These are normal genes that have a tendency to slow down the speed of cell division as well as correct any mistakes by the DNA in cells. Tumor suppresor genes are also responsible for the process of apoiptosis; this is the process through which cells are told when to die or self destruct. In event that the tumor suppressor genes in the body ate not functioning normally cell grow abnormally and result in cancer. 3.0.0 Genetic Cancer Screening

Definition


The genetic screening of cancer refers to the utilization of laboratory techniques and instruments in analyzing the DNA sequences in an individual’s genes with the intention of identifying the increased cancer risks that such sequences may expose the affected individual to (NHI Publication, 2007, p.1). The genetic screening of cancer is aimed at investigating DNA trasformations in cancer incidents. Genetic cancer screening tests are thus examine transformatiuons occuring solely in the cancer cells acquired from cancer patients. It is noteworthy that, as indicated by the American Cancer Society (2011, p. 2), the genetic screening used in the examination of cancer cells is different from that utilized in investigating the risk of inherited cancer. According to the American Society of Clinical Oncology (2003, p. 2397) genetic cancer screening makes use of medical tests to investigate mutations in an individual’s chromosomes or genes. Pelletier and Dorval (2004, p. 16) state that cancer screening tests are usually carried out for predictive purposes. The American Cancer Society (2011a, p. 1) reveals that predictive gene testing is usually carried out for purposes of investigang chromosomal mutations that put individuals to risks of developing certain diseases. For cancers such as breast cancer, genetic cancer screening may incline towards the analysis of BRCA1 and BRCA2 genes in females whose mothers of female siblings have had breast cancer (Struewing et al, 1997, 1402). Eligible Candidates for Genetic Cancer Screening


There are different categories of individuals that are perceived as the most suitable candidates for genetic cancer screening. One such category is comprised of those persons whose first degree family members for instance parents, siblings or children have been diagnosed with cancer, particularly if it is the same type of cancer. Individuals with a history of cancer in their family line that is associated with a single gene mutation for instance pancreatic, ovarian or breast cancer should also be screened. The American Cancer Society (2011a, p. 3) reveals that individuals with family members who were diagnosed with cancer at a very early age or those with relatives suffering from rare forms of cancers associated with hereditary cancer syndromes are also advised to undergo genetic cancer screening. In the event that particular gene transformations are known in an individual’s family, owing to the outcomes of genetic cancer screening by members of the individual’s family, it is advisable that the individual also undergoes genetic cancer screening. 4.0.0 Steps In Genetic Cancer Screening


Genetic cancer screening is usually carried our after the patient and their heath practitioners have agreed that it is the best thing to do. There are a number of important stages that typify the process of genetic cancer screening. Assessment of Risks This is the first step in genetic cancer screening; risk factors for cancer are determined by the history of cancer in one’s family line. In genetic cancer testing there are a number of elemts that are assessed for risk; these include lifestyle factors, detection actions as well as exposure to carcinogens and gynecologic past for women.

Genetic Counseling After the risk has been assessed the second step in genetic cancer screening is for the involved person to receive counselling on whether or not they should undergo the genetic screening of cancer as well as the process through which mutated genes that increase risk cancer for individuals are passed on from parents to their offspring. In the event that the risk for cancer is high counsellors are vested with the responsibility of advising the affected persons on its management, for instance, an adjustment of their lifestyle or in extreme cases preventive surgery. Informed Consent


After counselling an indivisual may make informed consent to the genetic cancer screening in writing. The American Cancer Society (2011b, p. 5) states that the patient should be sensitized on the reason for the screening, type of cancer being screened, benefits and challenges of screening, the accuracy of involved tests as well as the different treatment options that are available. Actual Testing In this fourth stage labarotary samples are collected for investigation. Struewing et al (1997, p. 1402) state that in genetic cancer screening the person being tested has to give several blood samples. The results of the tests are then given to doctors or genetic counsellors so that the patient can go through another session of counselling before being exposed to the results. The counseling process is discrepant depending on whether the test results are postive or negative. Positive or inconclusive results in genetic cancer screening imply that the patient be exposed to cancer detection tests and chemoprevention. American Cancer Society (2011b, p. 5) indicates that other patients may opt for prophylactic surgery to get rid of the canerous parts of their bodies. 5.0.0 Legal, Ethical and Social Implications of Genetic Cancer Screening American Cancer Society (2011b, p. 6) states that genetic cancer screening is characterized by a number of legal implications. According to the 21st May 2009 Genetic Information Nondiscrimination Act (GINA), discrimination by hirers or insurances of health based on a person’s genetic data is prohibited. Giarelli and Jacobs (2000, p. 460) affirm that predictive genetic screening of cancer can only be carried out when a patient decides to have it done. Medical experts such as oncology nurses and doctor are tasked with the responsibility of ensuring that they give patients information that is very objective and acurate so as to enable the patient and their families to make informed decisions on whether to ungergor the screening or not. Ethical implications in genetic cancer screening are mostly related to the patient-physician relationship. Patients expect that their doctors abide by the rules of confidentiality. Health practioners such as nurses, doctors and relevant counsellors also ought to abide by the rules of disclosure. There are a number of public and community resources that are established in regards to genetic cancer screening. In the year 2003 the Human Genome Project, a collaborative efforet by the public and private sector mapping out the entire human DNA sequence was completed. The National Coalition for Health Proffessional Education in Genetics (NCHPEG) is a group whose duty is to educate members of the society on emergent genetic knowledge and technology (American Cancer Society, 2011b, p. 8). 6.0.0 Conclusion This paper has offered a brief introduction on gene mutation and how it increases cancer risk factor in affected individuals. The phenomenon of genetic screening as well as the significance of gene mutation on genetic cancer screening has also been delibetated upon. The concept of genetic cancer screening has been deliberated upon in detail followed by the different steps in genetic cancer screening. Thie paper has also made a discussion of the legal, ethical and social implications of genetic cancer testing. It is important that appropriaete and feasible ethical, legals and social principles be formulated for purposes of ensuring that genetic cancer screening is carried out as per the stipulated regulatory and legislative decrees to ensure quality healthcare. 7.0.0 References American Society of Clinical Oncology, (2003), “American Society of Clinical Oncology policy Statement Update: Genetic Testing for Cancer Susceptibility”, Journal of Clinical Oncology, Vol. 21, pp. 2397−2406 American Cancer Society, (2011a), “Genetic Testing: What You Need to Know”, http://www.cancer.org/acs/groups/cid/documents/webcontent/002548-pdf.pdf [Accessed on 6th May 2013], pp. 1-10 American Cancer Society, (2011b), “Oncogenes, Tumor Suppressor Genes and Cancer”, http://www.cancer.org/acs/groups/cid/documents/webcontent/002550-pdf.pdf [Accessed on 6th May 2013] Cancer Support Community, (2011), “Hereditary Cancers”, Cancer Support Community- A Global Network of Education and Hope Giarelli E. and Jacobs, L. A., (2000), “Issues Related to the Use of Genetic Material and Information”, Oncology Nursing Forum, Vol. 27, pp.459−467 NHI Publication, (2007), “Genetic Testing: What it Means for Your health and for Your Family’s Health”, NHI Publication, No. 07- 6283, pp. 1-5 Palma M., Ristori E., Ricevuto E., Giannini G., Gulino A., (2006), “BRCA1 and BRCA2: The Genetic Testing And The Current Management Options For Mutation Carriers”, Critical Reviews in Oncology/Hematology, Vol. 57(1), pp. 1–23 Pelletier, S., and Dorval, M., (2004), “Predictive Genetic Testing Raises New Professional Challenges For Psychologists”, Canadian Psychology 45, pp. 16–30 Siegel, R., Naishadham, D and Jemal, A., (2013), “ Cancer Statistics: 2013”, Cancer Journal for Clinicians, Vol. 63, Issue 1, pp. 11- Struewing J.P., Hartge P., Wacholder S., et al, (1997), “The Risk Of Cancer Associated With Specific Mutations of BRCA1 and BRCA2 Among Ashkenazi Jews”, New England Journal of Medicin, Vol. 336(20), pp. 1401–1408