Lung Cancers And Its Effects

1288 WordsOct 22, 20156 Pages
INTRODUCTION What are lung cancers? Lung cancers are the abnormal cells which grow in uncontrolled manner in one or both lungs. They do not function as normal lung cells and do not develop into healthy lung tissue. The abnormal cells can grow, form tumours and interfere with the normal functions of the lung (Lungcancer.org, 2015). Lung cancers can be divided into two major types, namely non-small cell lung cancers (NSCLC) and small cell lung cancers (SCLC). NSCLC can be further classified into three main subtypes, namely adenocarcinoma, squamous-cell carcinoma and large-cell carcinoma (Longo & Harrison, 2012). Lung cancers can be diagnosed by chest X-ray, computerised tomography (CT) scan, positron emission tomography-computerised tomography (PET-CT) scan, bronchoscopy and biopsy (Nhs.uk, 2015). Unfortunately, lung cancers are often diagnosed at the later stages. This is due to the unrecognisable symptoms and warning signs at the earlier stages. NSCLC are often diagnosed at stage IV which accounts for 30-40% of cases whereas 60% of SCLC is diagnosed at stage IV. Lung cancer usually originates from the cells lining the bronchi, bronchioles and alveoli. Carcinogens especially tobacco smoke will alter the gene expression of the normal human lung cells, resulting in cell mutation. The proto-oncogenes will be converted to mutated form, oncogenes. Mutation leads to the decreased expression of the tumour suppressor genes. This results in uncontrolled cell proliferation, cell

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