Smoking and Lung Cancer Essay

3790 Words Jan 10th, 2013 16 Pages
Occupational lung cancer and smoking: a review in the light of current theories of carcinogenesis
ALAN C. CHOVIL, MA, MB, B CHIR MPH, DAB PREy MED

This paper considers modern theories of carcinogenesis as they apply to the induction of lung cancer by tobacco smoking and occupational exposure to carcinogens. Some of the known and postulated factors affecting carcinogenesis are discussed, with particular reference to syncarcinogenesis and thresholds. Factors affecting the intensity of smoking exposure are reviewed, and the generally accepted occupational lung carcinogens are listed. Relative risks for the various carcinogens according to smoking status (where known) are presented. The carcinogens are considered individually, and known or
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The evidence is largely epidemiologic and, while strong, is still questioned.2 It is also generally accepted that several types of industrial exposure are capable of causing lung cancer. The role that smoking plays in association with industrial hazards is less clear. There is a tendency for some of those associated with industry to play down the occupational risks and emphasize smoking.4 The tobacco industry and cigarette addicts tend to do the opposite. This paper will briefly review the current theories of carcinogenesis and explore the possible mechanisms of interaction between smoking and occupational hazards.

Factors in carcinogenesis Genetic mutation

Research has failed to show an association of viruses with most cancers that occur in humans. Currently the favourite theory is that most cancers arise as a result of genetic mutations, which may be induced by chemicals, ultraviolet or ionizing radiation, or the interaction of viral deoxyribonucleic acid (DNA) and cellular DNA, or may be congenital.5 Carcinogenic chemicals react with DNA because they are usually strongly electrophilic or alkylating. A number of known carcinogens require conversion to an active form in the organism. An example is benzolia]pyrene, one of the earliest carcinogens to be isolated. This substance is converted by a complex enzyme, aryl hydrocarbon hydroxylase, Reprint

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