A Review Of Lung Cancer Biology Essay

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Cancer cells can break off from the primary tumour and be spread to other areas of the body though the bloodstream. Just like the lymph system, blood vessels provide a network of channels all over the body. This allows the cancer cell to migrate to other important organs and cause secondary tumours to develop if it remains are untreated. Lung cancer if left untreated, it can spread to other parts of the body including lymph nodes, nerves and blood vessels. Compared with other cancers, lung cancer tends to metastasize much earlier. In fact, a significant number of lung cancer cases are detected due to symptoms of metastatic lung cancer. The most frequent metastatic sites for lung cancer are glands, the brain, bone and the liver. The spreading of lung cancer to the bones causes tremendous pain and can make affected bones break more easily. Lung cancer that metastasizes in the brain causes several neurological disorders including seizures, reduced vision, loss of control and sensation in certain body parts.

Lung cancer is a result of a mix of factors related to lifestyle a person lives. There are a number of factors that increase the chances of getting lung cancer. Lang caner is caused due to unhealthy life style this cancer is related to the use of tobacco (smoking). The majority of lung cancers occur in people who are either current or former smokers. While the relationship between smoking and lung cancer is well-established, other factors also come into play (Dollinger and Rosenbaum, pg 231-237). What type of food people eat and what they drink, individual's exposure to ultraviolet (UV) radiation from the sun, and, partially, exposure to cancer-causing agents (carcinogens) in their living environment? Some examples of these carcinogens are asbestos, uranium, arsenic, radioactive materials and certain petroleum products. Again, when smoking is combined with the exposure to these carcinogens, the risk of lung cancer is greatly increased. By not smoking, not consuming alcohol, limiting exposure to sunlight, by having a healthy well-balanced diet and a healthy lifestyle which includes exercise, a person can greatly reduce the risk of cancer. By reducing high-risk behaviour and changing your lifestyle to a healthier one, it is much less likely that you will contract lung cancer.

Cystic fibrosis is an inherited disease of the mucus glands that affects many body systems. The disorder's most common signs and symptoms include progressive damage to the respiratory system and chronic digestive system problems (Thomson, pg 54-57). Cystic fibrosis is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. Cystic Fibrosis is a very complicated and hard to treat disease due to the parts in the body organs it attacks. The disease itself is not contagious, and it will only manifest in the body if the person has two pairs of this gene, one from each parent (Bush, pg 112-114). Those having only one pair are carriers and will never develop this disease.

A disease is an illness or sickness caused by a virus, bacteria or parasite that presents with certain symptoms and physical signs. Diseases include such things as measles, mumps, chicken pox, cholera, dysentery, hepatitis A and poliomyelitis. Many of these diseases can be dealt with by the body's own defence system, but sometimes the body needs help as it is unable to combat the disease and this is when doctors prescribe antibiotics and other medications.

Question 3

The immune system protects human body from disease, viruses, bacteria, and parasites causing sickness. These vary from the ordinary flu cold, to death causing diseases such as the HIV, and the AIDS virus. The immune system is a complex system which includes specialized cells and a circulatory system known as the lymphatic system. The lymph vessels form a circulatory system that works in close partnership with the body's blood circulation system to clear infections from the body. The organs of the immune system are called lymphoid organs and it is in the lymphatic system that the cells needed to protect our body, the lymphocytes (white blood cells) are carried in a clear fluid called lymph.

When an antigen enters the body, it may be partly neutralized by components o the innate immune system. It may be attacked by phagocytes or by performed antibodies that act together with the complement system. The human immune system contains approximately 1 trillion T cells and 1 trillion B cells, located in the lymphoid organs and in the blood, plus approximately 10 billion antigen-presenting cells located in the lymphoid organs. To maximize the chances of encountering antigens wherever they may invade the body, lymphocytes continually circulate between the blood and certain lymphoid tissues (Sompayrac, pg 78-80). Lymphocyte spends an average of 30 minutes per day in the blood and recalculates about 50 times per day between the blood and lymphoid tissues.

Question 4

Stress can have negative effects on individuals' physical and emotional health such as greater susceptibility to infectious diseases, increased risk of heart attack or stoke, and damage to areas of the brain that affect memory. Exposure to numerous stressful events within a short period of time could have a detrimental effect on health. Too much stress can exceed the body's ability to cope, leading to illness. Reactions to stress vary between individuals, it is also known that men have a higher heart rate than women when introduced to stress, and they also tend to have more immune system problems. Some people also react more strongly to hassles, while others feel that life changes are more stressful. During stress the sympathetic, rather than the parasympathetic part of the autonomic nervous system is dominant.

During stress several things happen to the body, which include the following: an increase in; heart rate, blood pressure, respiration and muscle tension, and a decrease in the movement of the stomach muscles, a constriction of the blood vessels, and a release of the hormones, epinephrine (adrenaline), and cortisol. These hormones in turn release fats and glucose into the blood stream for energy.

Looking at what happens during stress, it is observed that why stress is a major contributor to both cancer and heart disease. Not only does long term stress lower the immune system for an extended time, making it impossible to fight cancer cells, but it is believed that stress may actually promote the growth of cancer cells. Because stress also constricts blood vessels, and releases fats into the blood stream, it causes blocked arteries, blocked arteries cause heart attacks. Long-term or chronic stress causes too much wear and tear resulting in decreased functioning of the immune system (Arnetz, pg 125-129). However, it is found that chronic psychological stress resulted in higher levels of cortisol, prolactin, and endorphin, an increased number of lymphocytes, and an augment in activated phenotype within B cell, T cell, and NK cell populations in people displaced by war. This finding suggests that chronic psychological stress induces strengthening of immune functions.

Long-term or chronic stress suppresses the immune system by changing stress hormones that tend to suppress or damage disease-fighting cells, making individuals more susceptible to infections and illness. Furthermore, weaken immune system under stress can cause cancer cells' progression. Overall, one critical question is how can stress produce a health-promoting response at one time and a health-defeating response at another. Stressful situations will always occur throughout life. However poor stress management can have negative effects on health, efficiency of decision- making, amicable interpersonal relations, or work efficiency.

The means of diagnosis includes biopsy, sputum analysis, bronchoscopy, electron microscopy and immunohistochemistry. Typical symptoms include cough, sputum production, and airway obstruction. The preferred treatment is surgical resection, although after metastasis has taken place, total surgical resection is difficult and survival rates dramatically decrease. Although chemotherapy has limited effectiveness, adjuvant treatment with newer agents has been shown to improve survival and quality of life. The tumours are usually smaller than 4 cm and may be asymptomatic, or cause chest pain and shortness of breath. Surgical resection is possible in a high proportion of cases, but because metastasis occurs early, the 5 years survival rate is less than 10 per cent. Newer chemotherapeutic agents are resulting in increased survival rates. Large Cell Carcinoma Large cell carcinomas constitute roughly 10 per cent of bronchogenic carcinomas. The growth rate is rapid with metastasis being early.

Once metastasis has occurred, surgical therapy is limited to comfort measures designed to relieve obstructive pneumonitis or prevent recurrence of pleural effusion (Gutman, pg 154-159). Neither radiation therapy nor chemotherapy has been successful in increasing survival. With treatment however, approximately 10 per cent of individuals are alive at 2 years. The primary treatment is chemotherapy and radiation therapy. Staging and grading Clinical manifestations in defining the staging and grading of lung neoplasms, it is helpful to review clinical manifestations.

Bronchial irritation most often causes coughing or wheezing. Local extension into the pleural cavity can cause lung compression, lung infection, and pain or paralysis of muscles in the diaphragm or vocal cords. Distant metastases produce symptoms that are specific to the organs involved. Systematic symptoms include weight loss, anorexia, and malaise. Lung neoplasms can also cause over secretion of various hormones such as polypeptide (resulting in hypercalcaemia), ACTH (resulting in over stimulation of the adrenals, and antidiuretic hormone (resulting in excessive water retention). about 15 per cent of patients with lung cancer, have no obvious symptoms and the tumour is discovered during routine chest examination.

Copper-67, a radioactive isotope, is the key element in a new method of early detection and treatment of lung cancer. The approach uses porphyrin, a synthetic compound, to deliver the radioactive copper to cancerous lung cells (Williams, pg 71-75). Once inside the cancer cells, the porphyrin releases its radioactive contents and kills the cancer with radiation. The method is able to detect tumours when they are too small to show up on chest X-rays. Immunotherapies several immunotherapies are currently being investigated.

The link between smoking and lung cancer is undeniable, and the importance of preventative measures cannot be underestimated. However understanding of the staging and grading with regard to prognosis and treatment of lung neoplasms, along with medical and technological advances is leading to better treatment modalities for this devastating illness.

Work Cited

Williams, Chris; (2010) Lung Cancer (The Facts), Oxford University Press, ISBN-10: 0199569339, pg 71-75.

Roth, A. Jack and Hong, Waun; (2008) Lung Cancer, Wiley-Blackwell; 3 editions, ISBN-10: 1405151129, pg 231-237.

Dollinger, Malin and Rosenbaum, Ernest; (2008) Everyone's Guide to Cancer Therapy; Revised 5th Edition: How Cancer Is Diagnosed, Treated, and Managed Day to Day, Andrews McMeel Publishing, ISBN-10: 0740768573, pg 589-593.

Gutman, Howard; (2009) Lung Cancer and Mesothelioma, Howard A. Gutman, ISBN-10: 1441515895, pg 154-159.

Thomson, Anne; (2008) Cystic Fibrosis (Facts), Oxford University Press, ISBN-10: 0199295808, pg 54-57.

Bush, Andrew; (2005) Cystic Fibrosis in the 21st Century, S. Karger AG, ISBN-10: 3805579608, pg 112-114.

Sompayrac, Lauren; (2008) How the Immune System Works, Wiley-Blackwell, ISBN-10: 140516221X, pg 78-80.

Arnetz, Bengt; (2006) Stress in Health and Disease, Wiley, ISBN-10: 3527312218, pg 125-129.