Lung cancer currently ist he leading cause of cancer related death in both sexes. Most lung cancers start growing in epithelial cells lining the bronchial lumen. Lung cancer is divided into two main groups: Small cell lung cancer (SCLC) Non-small cell lung cancer (NSCLC). SCLC tends to be an aggressive cancer and is highly associated with tobacco smoking. The majority of lung cancers are NSCLC which are again subdivided into three categories: squamous cell carcinoma, adenocarcinoma, and giant lung cell carcinoma. Smoking and second-hand smoke are the leading risk factors for development of lung cancer. Lung cancer risk is higher if there is positive familiy history of diagnosed relative with lung cancer. Substances such as radon and asbestos also increase lung cancer risk. Chronic lung diseases have also been implicated through inflammation mediation as a lung cancer risk. Advanced stage lung cancer symptoms are ususally one of following: persistent cough, hemoptysis, chest pain, voice change, recurrent pneumonia or bronchitis. Common methods for detectiom are chest x-ray, chest CT scan, bronchoscopy, and sputum cytology. A tissue biopsy of the lung is examined by a pathologist in order to bring definitive diagnosis .NSCLC uses the T/N/M staging system which assigns a degree of severity based on size, lymph node involvement, and spread of the cancer. SCLC is diagnosed as either limited or extensive depending on the spread of the cancer. Many genetic, and epigenetic changes occur in cancer. Alterations in Ras, Myc, Rb, TP53, and EGFR have been implicated in the development of lung cancer. Lung cancer treatments include modalities such as surgery, chemotherapy and radiation therapy.