Fig.1 Lung cancer
Lung cancer, also named as lung carcinoma, is characterized by uncontrolled cell growth in the tissues of lung. The two major types are small-cell lung carcinoma (SCLC) and non-small-cell lung carcinoma (NSCLC), which are malignant lung tumor. The most obvious symptoms are coughing (coughing up blood included), shortness of breath, chest pains and weight loss. The vast majority (85%) of lung cancer are on account of long-term tobacco smoking. Around 10–15% of cases occur in those who have never smoked before. These cases are often caused by a combination of genetic factors and exposure to harmful gas, such as: radon gas, second-hand smoke, asbestos or other forms of air pollution. Mutations in the K-ras proto-oncogene account for 10–30% of lung adenocarcinomas. Around 4% of non-small-cell lung carcinomas are considered to involve an EML4-ALK tyrosine kinase fusion gene. Tumor markers, such as CEA and CYFRA 21-1 are of great diagnostic value in primary lung cancer.