Genetic Polymorphisms in the Nicotinic Receptors and Lung Cancer: an Overview

Abstract

Introduction: Lung cancer is the most common malignant tumor. It was responsible for 20,485 deaths in 2008 in Brazil and 90% of diagnosed cases are associated with tobacco consumption. Nicotine is the primary component of tobacco in cigarettes and variants in the genes that encode subunits of the nicotinic acetylcholine receptor participate in both etiology and progression of lung cancer. Objective: To carry out a review about lung cancer and single nucleotide polymorphisms in genes which encode subunits of the nicotinic acetylcholine receptors. Method: A review in literature of articles published in the last five years, in English and in researches with human beings, through electronic search at PubMed database. Results: The 15q25 region contains single nucleotide polymorphisms of the CHRNA5, CHRNA3 and CHRNB4 genes and is associated with risk of lung cancer and nicotine addiction. There is a strong association between single nucleotide polymorphisms 1192G>A and 645C>T from CHRNA5 and CHRNA3 genes respectively, and lung cancer. Other polymorphisms in 15q25 associated with this kind of cancer include: 24289A>G, 28757T>C, 14621A>C, 10611T>C and 5539C>G from the CHRNA5 gene27011C>T, 3393G>A, 30238C>T from the CHRNA3 gene and 49711634C>G from the CHRNB4 gene. Conclusion: The studies published suggested that in the investigation of single nucleotide polymorphisms, both ethnicity and functional effect of that variant should be considered to the functioning and genic expression.