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
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
Haiyan Yang 0 1 2
Ruo Feng 0 1 2
Haiyu Wang 0 1 2
Yadong Wang 0 1 2
0 R. Feng Department of Histology and Embryology, School of Basic Medicine, Zhengzhou University , Zhengzhou 450001 , People's Republic of China
1 H. Yang Department of Epidemiology, School of Public Health, Zhengzhou University , Zhengzhou 450001 , People's Republic of China
2 We read with great interest the paper titled X-ray repair cross- complementing group 1 Arg194Trp polymorphism is associ- ated with increased risk of lung cancer in Chinese Han popu- lation 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 inter- esting study
3 ) Department of Toxicology, Henan Center for Disease Control and Prevention , No. 105 of South Nongye Road, Zhengzhou 450016 , People's Republic of China
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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 [36] 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 1.091.46) 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
0.901.22 and OR = 1.12, 95 % CI 0.951.31,
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
Fig. 1 Forest plots for the
association between XRCC1
Arg194Trp polymorphism and
lung cancer risk in Chinese
population (a Trp/Trp vs. Arg/
Arg, b Arg/Trp vs. Arg/Arg, c
Arg/Trp+Trp/Trp vs. Arg/Arg)
the analysis to the studies with controls in agreement with
Hardy-Weinberg equilibrium (HWE), we did not observe
any association between XRCC1 Arg194Trp
polymorphism and lung cancer risk (Table 2).
Characteristics of selected papers
HWE Hardy-Weinberg equilibrium
Source of control
Number of case
Number of control
Publication bias was assessed by funnel plots. The shape of
funnel plots seemed to be approximately symmetrical
(Fig. 2ac). The results from Eggers test and Beggs test
signified that publication biases might have few effects on this
current meta-analysis (Table 2).
Sensitivity analyses were performed to identify the effects of
the individual dataset on the summary estimates by sequentially
removing each study. The summary effects were not modified
when the studies were homogenous for Arg/Trp vs. Arg/Arg
and Trp/Trp+Arg/Trp vs. Arg/Arg polymorphisms among total
Case/control Heterogeneity test Summary OR (95 % CI) Hypothesis test df
Total
Trp/Trp vs. Arg/Arg 2776/2950
Arg/Trp vs. Arg/Arg 4130/4495
Trp/Trp+Arg/Trp vs. Arg/Arg 4591/4899
Stratification by HWE
Yes
Trp/Trp vs. Arg/Arg 2418/2531
Arg/Trp vs. Arg/Arg 3677/3950
Trp/Trp+Arg/Trp vs. Arg/Arg 4058/4302
Stratification by source of control
Healthy subject-based control
Trp/Trp vs. Arg/Arg 1997/2204
Arg/Trp vs. Arg/Arg 2 (...truncated)