Genetic Analysis and Cancer Medicine †Free Samples to Students

Question: Discuss about the Genetic Analysis and Cancer Medicine. Answer: Introduction Incidence of cancer occurs due to the mutation in the nucleotide sequence. During the replication of DNA, though the fidelity of the process is high and there are several proofreading and repair mechanisms at work, the possibility of a mutation cannot be ruled out. Some mutations cause change in gene function and can result in cancer. The uncontrolled growth of cells in number causes malignancy and people suffer from cancer. The statistics of cancer occurrence shows an upward trend. As a result the diagnosis and treatment management of cancer have improved considerably and a patient can be treated to achieve reduced mortality. An ageing population leads to increase in the incidence of cancer. Other causes of increase in cases of cancer are smoking, obesity, poor diet and lack of exercise and a lifestyle that is unhealthy. Although these causes are known there is little change in individual behaviour and population behaviour. These reasons have made cancer a public health problem in t he world and in Australia. It is now understood that rather having to go through the difficult procedures of treatment and the discomfort and pain associated with cancer, it is better to work on a public health strategy that can prevent the incidence of cancer. Adoption of better lifestyle, better nutrition and remaining physically active are some such steps. Replication of DNA occurs before cell division and in eukaryotic cells the lengthof the DN to be replicated is very high and so several origins of replication begin the process simultaneously to ensure that all regions are replicated. During replication, the deoxynucleotides dATP, dTTP, dCTP and dGTP are added one at a time due to the action of the enzyme DNA polymerase III. Several checks ensure that the added nucleotide is exactly complementary to the base on the template strands which can be read due to unwinding of the DNA double helix. But even then sometimes incorporation of a wrong base occurs. The proofreading ability of the DNA polymerases helps identify the mistake and it is then repaired through one of the many repair mechanisms. The epsilon subunit of DNA polymerase III plays a role in exonuclease activity that helps in the removal of wrongly incorporated nucleotides. If the repair and proof reading machinery are unable to detect mismatch, a mutation occurs. Some mutations may not cause any harm if they are located in the non-coding regions of the DNA but if a single mutation occurs in the coding region, it can change the polypeptide sequence that is expressed. So, a mutation is an inheritable change in the nucleotide sequence of DNA. Other than mistakes during the process of replication some mutations occur spontaneously and result in an altered nucleotide sequence. DNA damage or dimerization of pyrimidines occurs due to exposure the UV fraction of sunlight, particularly in the DNA of skin cells. Excision repair, recombinatorial repair and error prone repair are mechanisms management that correct the mistakes in the DNA sequence. Normal cells do not divide unless there is an injury but cancer cells continue to divide and invade other tissues when growing. Size of cancer cells and their nuclei is larger or smaller than the normal cells. There is no cell to cell communication between cancer cells and they have the ability to metastasize and spread to other regions of the body. While normal cells respire aerobically, cancer cells respire anaerobically and can evade the immune system. The cancer cells do not perform normal functions, for eg., if the normal function of a cell is to produce the hormone thyroxine, a cancer cell of the thyroid gland may not produce the hormone (Kufe, et al., 2003). Although all cancers are caused due to mutation/s. The causes of mutations can be varied. Smoking, exposure to radiation, exposure to carcinogens, obesity, chronic inflammation, due to poor diet and lack of exercise are the main reasons of occurrence of mutations in tissues. The immune system either is unable to recognize a cancerous growth or the cancer cells are able to evade the immune response. Exposure to sunlight can also cause cancer of the skin. Some cancers are inheritable and it is possible to calculate risks of getting an inheritable cancer by genome analysis. Some examples of inherited cancers are breast cancer, ovarian cancer, and colorectal cancer (Cancer.org, 2017). Treatment of cancer involves killing of the cancer cells by chemotherapy or a combination of chemotherapy and radiation therapy. Some treatments involve immunotherapy through monoclonal antibodies. Other treatments may also include or consist of hormonal therapy. In many cases surgery may be performed to remove a cancerous or malignant tumor and the surgery may be followed by therapy includes one or a combination of the above therapies (Cancer.gov, 2017). Commonly diagnosed cancers in Australia The highest incidence of cancers in Australia are prostate cancer among men or breast cancer among women, colorectal cancer and lung cancer. Melanoma also occurs at a high frequency. 48 cases of skin cancer per 100,000 people in Australia is among the highest rates of incidence in the world. The rise in cases of cancer has been largely attributed to higher life expectancies that have resulted in an ageing population and better methods of screening. In 2012, about 40,000 Australians died due to cancer. Mortality due to cancer has surpassed the number of deaths due to cardiovascular disease. The estimated number of cancer cases diagnosed in 2017 is 134174, of which 72169 cancers were diagnosed in males and 62005 were diagnosed in female patients. Of these, 17586 cases were those of breast cancer in females, 16682 cases of bowel or colorectal cancer, 16665 cases were those of prostate cancer and 12434 cases were cancers of the lungs. 13941 cases of melanoma were also diagnosed (Cancerau stralia.gov.au, 2017). Basal cell carcinoma (BCC) and the somatic cell carcinoma (SCC) are not notifiable cancers in Australia (Cancer.org, 2016). Australia has the highest incidence of skin cancer in the world. The incidence of prostate cancer and breast cancer is highest among men and women respectively. The high incidence is due to increase in life expectancy. As the number of the aged in the population grows, the incidence of these cancers has also resulted in an increase. Another reason for increase in the number of diagnosed cases is that better diagnostic methods and more frequent screenings are able to find cases that remained undiagnosed in the previous decades. The changes in lifestyle, diet and lack of physical exercise are the main risk factors that have increased the number of cancers. An increase in the number of obese individuals has also increased cancer cases in Australia (Aihw.gov.au, 2017). Prevention of cancer is the best way to combat the rising number of cancers. Most ways in which cancer can be prevented are already understood. Cessation of smoking, following a healthy lifestyle that includes a healthy diet and physical activity are the main steps. Active screening that is age -appropriate has been recommended and if symptoms are recognised early, it is possible to reduce prevalence of cancer. The area where most work remains to be done is change in lifestyles of individuals, implementation of better public health policies and registering a change in population behaviour (Colditz, et al., 2012). Conclusion The molecular basis of cancer is well understood and mutations are understood to cause cancer. The individual behaviours that increase the risk of cancer have also been identified. The incidence of cancer and mortality management due to cancer in Australia is on the rise. Statistics show that breast cancer and prostate cancer are high on the list of incidence and bowel cancer is also a major health threat. Although diagnosis and treatment are available, prevention of cancers is the best possible public health approach to cancer. References Aihw.gov.au, 2017. related-material. [Online] Available at: https://www.aihw.gov.au/reports/cancer/cancer-in-australia-2017/related-material [Accessed 2 October 2017]. Cancer.gov, 2017. treatment. 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