Lung cancer is a malignant neoplasm of the lung tissue characterized by an uncontrolled cell proliferation. It is also referred to as carcinoma of the lung. This neoplasm arises from epithelia of the lungs, bronchi and trachea. Lung cancers can be of epithelial cell origin (carcinoma) or mesothelial cell origin (malignant mesothelioma). Lung cancer begins with inactivation of tumor suppressor genes or with activation of oncogenes. Carcinogens bring about mutation in the genes that induce development of cancer.
About 30 percent of lung adenocarcinomas are brought about by a mutation in the K-ras proto-oncogene. It has also been reported that epigenetic alterations that happen on genes may lead to inactivation of tumor suppressor genes. This, therefore, implies that proliferation of cells will be uncontrollable leading to lung cancer. The epidermal growth factor receptor (which functions to regulate apoptosis, cell proliferation and tumor invasion) undergoes mutation. This means that there will be no apoptosis, cells will excessively proliferate, and tumors will grow. This may develop into malignancies later.
There are two types of lung cancers i.e. small cell lung cancer (that is exclusively associated with heavy smokers) and non-small cell lung cancer (that includes adenocarcinoma, large cell carcinoma and squamous cell carcinoma). Just …show more content…
According to cdc.gov, the main cause of lung cancer is smoking. Cigarette smoking has been seen to be associated with a large number of lung cancers. It affects both active and passive smokers. Other causes include air pollution and genetic factors. Air pollution with carcinogenic gases causes lung cancer. Smoke from fossil fuels, some insecticides, and asbestos dust have been identified to among the causative agent of lung cancer. People living in industrialized urban areas have been shown to have a higher risk of getting lung cancer than those living in unindustrialized