YOU often cough that never stopped, even to bleed? Also shortness of breath, fever, and weight loss? If yes, do not say anything. Do not underestimate these things! Because the condition can be symptoms of lung cancer, silent killer that is still difficult to cure. The lungs are organs in the respiratory system that functions to exchange oxygen in the system of carbon dioxide from the blood with the help of hemoglobin. This process is known as respiration or breathing. The lungs are located in the thoracic cavity, protected by the bony structure of the clavicle wall as a pleural fluid. 
Lung cancer is a tumor that grows in the lungs largely derived from cells in the lungs. Lung cancer can also come from cancer in other body parts that spread to the lungs. The cause of this disease can come from many factors, namely internal and external (environment). Internal factors heavily influenced by ourselves, whether it is genetic or in the body. While many external causes of air pollution comes from and the chemicals are inhaled, especially from cigarette smoke.
As reported by the Health Day, Wednesday (20/1/2010), in a recent study provides information about how the tobacco in cigarettes contains a substance triggers cancer took a big hand in this deadly outbreak. This substance triggers cancer more with a carcinogen. Nitrosation of nicotine or metabolites in the human body can cause the formation of two carcinogenic tobacco-specific nitrosamine-n’-nitrosonornicotine (NNN) and 4 – (methylnitrosamino) -1 – (3-pyridyl)-1-butanone (NNK). NNK contributes to the formation of tumors of lung cancer.
Researchers at the National Cheng Kung University in Taiwan reported that NNK contributes to the accumulation of proteins, called DNMT1, which was in the cell nucleus. In turn, NKK will turn off the gene that makes DNMT1 form tumors. Researchers led by Wang Yi-Ching said, they found evidence supporting the theory in mice given tumor NNK, in patients with lung cancer were smokers. Patients with lung cancer who were heavy smokers have a higher level of DNMT1 expression and tend to have poor prognosis.
