Lung cancer
Cancer is a class of diseases characterized by out-of-control cell growth, and lung cancer occurs when this uncontrolled cell growth begins in one or both lungs. [1]
Lung cancer is a disease characterized by uncontrolled cell growth in tissues of the lung. [2]
Passive inhalation (”secondhand smoke”) is linked to lung cancer in nonsmokers. [3]
Since lung cancer tends to spread or metastasize very early after it forms, it is a very life-threatening cancer and one of the most difficult cancers to treat. [4]
Definition of lung cancer: Cancer that forms in tissues of the lung, usually in the cells lining air passages. [5]
Rather than developing into healthy, normal lung tissue, these abnormal cells continue dividing and form lumps or masses of tissue called tumors. [1]
Tumors can be benign or malignant; when we speak of “cancer,” we are referring to those tumors that are malignant. [4]
Heavy smoking and starting smoking earlier in life increase the risk. [3]
The white area in the upper lobe is cancer; the black areas are discoloration due to smoking. [2]
It has been estimated that cigarette smokers have a ten-fold higher risk of lung cancer, in comparison with nonsmokers. [3]
Sources:
[1] What is Lung Cancer? What are the Symptoms of Lung Cancer?
[2] Lung cancer - Wikipedia, the free encyclopedia
[3] lung cancer: Information from Answers.com
[4] abdominal diseases: Lung Cancer
[5] Lung Cancer - National Cancer Institute