A new study revealed the amount of damage that smoking can cause on a person's DNA and examined how tobacco smoke affects the cells of the human body. If an individual can consume a pack of cigarettes every day in a year it can widely cause of multiple changes in the cells within the various parts of the body. The cells that are directly exposed to smoke are mostly damaged, with 150 mutations have found occur in lung cells in just one year, 97 mutations in the larynx and 39 mutations in the oral cavity.

According to Ludmil Alexandrov, who led the study and from Los Alamos National Laboratory in Los Alamos have said that the Tobacco smoking damages the DNA in organs that are exposed to smoke both direct and indirect. So, it accelerated the occurrence of the genetic mutations and increased the risk of having cancer.

Smoking is a risk factor for 17 types of cancer and is estimated to kill 6 million individual every year. Tobacco has a mixture of chemicals in which 60 are known to be as carcinogens and can cause cancer by aiding the existence of mutations in genes and in an increased number of mutations that are most likely develop into cancer-causing genes. People who smoke one pack a day develop an average of extra 150 mutations in their lungs every year, which explains as to why smokers have a higher risk of acquiring lung cancer, CNN has reported.

Researchers scanned genome sequences of more than 5,000 tumors from the 17 types of cancer, these were acquired from nonsmokers and smokers for comparison. The analysis found a range of 'molecular signatures' or a pattern that are really different from sequences in DNA that were linked to people who smoke. One signature found in tissues that directly exposed to smoke and the unrecognized signature was found in all smoking-related cancers and appeared to have increased the rate of the premature mutations and correlate with age.

David Phillips, a professor of environmental carcinogenesis at Kings College London, said that the results revealed a connection between the direct and indirect effects. Researchers also looked at any changes in DNA methylation, it is a process in which a molecule that is known as methyl group sits on the surface of the DNA to encourage gene activity - and saw a limited difference between the nonsmoker and smoker, according to 5 News.

According to Dr. James Flanagan, a cancer geneticist at Imperial College London believes that methylation has no role in the presumptive changes of the genes whether it is active or silent. Sir Mike Stratton, a director of the Wellcome Trust Sanger Institute in the UK said that this study tells that looking in the DNA of cancers can provide new clues to how cancer developed and how they can be prevented.