Note of clarification of data in the paper titled X-ray repair cross-complementing group 1 Arg194Trp polymorphism is associated with increased risk of lung cancer in Chinese Han population.

Abstract

We read with great interest the paper titled “X-ray repair crosscomplementing group 1 Arg194Trp polymorphism is associated with increased risk of lung cancer in Chinese Han population” published in Tumor Biol. 2013, 34: 2611–2615 [1].Wu et al. performed a meta-analysis to investigate the association between X-ray repair cross-complementing group 1 (XRCC1) Arg194Trp polymorphism and lung cancer risk in Chinese Han population on the basis of 12 case-control studies with 4385 cases and 4545 controls. The authors found that XRCC1 Arg194Trp polymorphism was associated with increased risk of lung cancer in Chinese Han population under three main models (allele contrast model, odds ratio (OR)=1.12, 95 % confidence interval (CI) 1.00–1.26, P=0.049; homozygote model, OR=1.27, 95 % CI 1.09–1.48, P=0.003; recessive model, OR=1.26, 95 % CI 1.09–1.46, P=0.003) when all eligible studies were pooled into meta-analysis. It is an interesting study. Nevertheless, a careful examination of the data provided by Wu et al. (Fig. 1 in the original text) [1] revealed two key issues that are worth noticing. Firstly, one overlapping paper [2] was not properly excluded from Wu et al.’s study [1]. Secondly, four eligible papers [3–6] published before 2013 were not included in Wu et al.’s study [1]. Therefore, the conclusions by Wu et al. [1] are not entirely reliable. In order to obtain a precise estimation of the relationship between XRCC1 Arg194Trp polymorphism and lung cancer risk in Chinese population, a meta-analysis was re-conducted on the basis of a total of 16 studies with 4591 cases and 4899 controls, which may provide comprehensive evidence for the association of XRCC1 Arg194Trp polymorphism with lung cancer risk in Chinese population. Table 1 listed the general information of selected studies. Table 2 listed the summary odds ratios of the association between XRCC1 Arg194Trp polymorphism and lung cancer risk in Chinese population. Overall, we observed an increased lung cancer risk in Chinese population among subjects carrying XRCC1 194 Trp/Trp genotype (OR=1.26, 95 % CI 1.09–1.46) comparing with Arg/ Arg genotype carriers in total population (Fig. 1a). We did not observe any association of Arg/Trp vs. Arg/Arg and Trp/Trp+Arg/Trp vs. Arg/Arg polymorphisms with lung cancer risk in Chinese population (OR=1.05, 95 % CI 0.90–1.22 and OR=1.12, 95 % CI 0.95–1.31, respectively) (Fig. 1b, c). In the subgroup analysis by a source of control, we observed an increased risk of XRCC1 194 Trp/Trp vs. Arg/Arg polymorphism for lung cancer in a healthy subject-based study (OR=1.34, 95 % CI 1.13– 1.59) (Table 2); we did not observe any association between XRCC1 Arg194Trp polymorphism and lung cancer risk in additional subgroup analyses (Table 2). Limiting H. Yang Department of Epidemiology, School of Public Health, Zhengzhou University, Zhengzhou 450001, People’s Republic of China