Lung Cancer
Lung cancer, also known as lung carcinoma, is a malignant lung tumor characterized by uncontrolled cell growth in tissues of the lung. Lung carcinomas derive from transformed, malignant cells that originate as epithelial cells, or from tissues composed of epithelial cells. Other lung cancers, such as the rare sarcomas of the lung, are generated by the malignant transformation of connective tissues, which arise from mesenchymal cells. Lymphomas and melanomas can also rarely result in lung cancer. In time, this uncontrolled growth can metastasize either by direct extension, by entering the lymphatic circulation, or via hematogenous, bloodborne spread – into nearby tissue or other, more distant parts of the body. Most cancers that originate from within the lungs, known as primary lung cancers, are carcinomas. The two main types are small-cell lung carcinoma and non-small-cell lung carcinoma. The most common symptoms are coughing, weight loss, shortness of breath, and chest pains.
