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Biology Articles » Health and Medicine » Illnesses and Pathobiology » Lung Cancer - when your normal cells turn against you
By Vicki Mozo
Does smoking lead to lung cancer? This is truly a heated debate you've
probably watched from documentaries (even read in fictional stories such
as in John Grisham's The Runaway Jury). Amidst the high number of
people smoking, many of them refute this notion since not all smokers
eventually develop lung cancer. Nevertheless, an epidemiological study
by NIH has found that a pattern depicting the growing number of smokers
accord to that of the mounting number of lung cancers (see figure).
Other independent research groups have also found a strong correlation
between lung cancer and cigarette smoking, with about 90% lung cancer
mortality is linked to smoking.3 Thus, an assumption that
smoking is one of the major causes of lung cancer persists since several
cases of lung cancer involve individuals who are smokers. If they are
correct, how come not all smokers develop lung cancer? Presumably, the
reason lies on the various factors that predispose the individual to
develop cancer, as well as the extent and history of cigarette smoking
comes to play.
NIH graph showing the correlation and time-lag between tobacco smoking and lung cancer rate in the U.S. male population.[Source: Wikipedia]
A typical cigarette or tobacco contains an overwhelming number of
carcinogens; the two most important chemical compounds in a tobacco
smoke include the nitrosamines and benzopyrene.4 A person
exposed to these compounds is at risk to forming lung cancer but the
likelihood depends on the extent of exposure over time. The longer is
the exposure to cigarette carcinogens the higher is the probability a
lung cancer will develop.
Cigarette or tobacco smoking is not only the major factor leading to
lung cancer. Another major factor is the quality of air we breathe.
Inhaling air pollutants, such as radon, can lead to mutations and
subsequently to lung cancer. Radon, a radioactive gas, is in fact, the
second leading factor associated with lung cancer.5
Certain respiratory diseases such as asbestos-related lung disease and
viral infections can also lead to lung cancer. Asbestos are toxic and
dangerous to health when inhaled by damaging lung tissues. Human
papillomavirus, simian virus 40, and cytomegalovirus, are some of the
viruses associated with lung cancer by disrupting the cell cycle process
or by inhibiting apoptosis.
Mozo V. 2011 May 20. Lung Cancer - when your normal cells turn against
you [Internet]. Biology-Online.org; [cited yyyy mmm dd]. Available from
This article is intended to provide information and individual
opinion of the author (and not of the site). Seek professional or
medical advice, diagnosis or treatment as necessary.
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