CYP1A1 MspI and exon7 gene polymorphisms and lung cancer risk: an updated meta-analysis and review

• Published in: Journal of experimental & clinical cancer research Vol. 30; no. 1; p. 99
• Main Authors: Zhan, Ping, Wang, Qin, Qian, Qian, Wei, Shu-Zhen, Yu, Li-Ke
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 20.10.2011; BioMed Central; BMC
• Subjects: Case-Control Studies; CYP1A1; Cytochrome P-450 CYP1A1 - genetics; Deoxyribonuclease HpaII - metabolism; Diagnosis; Exon (Molecular genetics); Exons - genetics; Female; Genetic aspects; Genetic polymorphisms; Humans; Lung cancer; Lung Neoplasms - genetics; Lung Neoplasms - metabolism; Male; Meta-analysis; Meta-Analysis as Topic; Physiological aspects; Polymorphism; Polymorphism, Genetic - genetics; Risk Factors; Susceptibility; China
• ISSN: 1756-9966; 0392-9078; 1756-9966
• DOI: 10.1186/1756-9966-30-99

Many studies have examined the association between the CYP1A1 MspI and exon 7 gene polymorphisms and lung cancer risk in various populations, but their results have been inconsistent. To assess this relationship more precisely, a meta-analysis and review were performed. The PubMed, Embase, Web of Science, and CNKI database was searched for case-control studies published up to June 2010. Data were extracted and pooled odds ratios (OR) with 95% confidence intervals (CI) were calculated. Ultimately, 64 studies, comprising 18,397 subjects from 49 case-control studies of the MspI genotype and 18,518 patients from 40 case-control studies of the exon 7 genotype, were included. A significantly elevated lung cancer risk was associated with 2 MspI genotype variants (for type C vs. Type A: OR = 1.26, 95% CI = 1.12-1.42; for types B and C combined vs. Type A: OR = 1.20, 95% CI = 1.13-1.28) in overall population. In the stratified analysis, a significant association was found in Asians, Caucasians, lung SCC, lung AC and Male population, not in mixed population, lung SCLC and female population. However, inconsistent results were observed for CYP1A1 exon7 in our meta-analysis, two variants of the exon 7 polymorphism were associated with a significantly higher risk for lung cancer (for Val/Val vs. Ile/Ile: OR = 1.24, 95% CI = 1.09-1.42; for (Ile/Val +Val/Val) vs. Ile/Ile: OR = 1.15, 95% CI = 1.07-1.24) in overall population. In the stratified analysis, a significant assocation was found in Asians, Caucasians, lung SCC and Female population, not in mixed population, lung AD, lung SCLC and Male population. Additionally, a significant association was found in smoker population and not found in non-smoker populations for CYP1A1 MspI and exon7 gene. This meta-analysis suggests that the MspI and exon 7 polymorphisms of CYP1A1 correlate with increased lung cancer susceptibility and there is an interaction between two genotypes of CYP1A1 polymorphism and smoking, but these associations vary in different ethnic populations, histological types of lung cancer and gender of case and control population.