Association between 3801T>C Polymorphism of CYP1A1 and Idiopathic Male Infertility Risk: A Systematic Review and Meta-Analysis

<div><p>Background</p><p>Epidemiological studies have evaluated the association between 3801T>C polymorphism of CYP1A1 gene and the risk for idiopathic male infertility, but the results are inconclusive. We aimed to derive a more precise estimation of the relationship by conducting a meta-analysis of case-control studies.</p><p>Methods</p><p>This study conformed to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. PubMed, Embase and CNKI databases were searched through November 2013 to identify relevant studies. Pooled odds ratios with 95% confidence intervals were used to assess the strength of the association between CYP1A1 3801T>C polymorphism and idiopathic male infertility risk. <i>Q</i>-test was performed to evaluate between-study heterogeneity and publication bias was appraised using funnel plots. Sensitivity analyses were conducted to evaluate the robustness of meta-analysis findings.</p><p>Results</p><p>Six studies involving 1,060 cases and 1,225 controls were included in this meta-analysis. Overall, significant associations between 3801T>C polymorphism and idiopathic male infertility risk were observed in allelic comparison (OR = 1.36, 95% CI: 1.01–1.83), homozygous model (OR = 2.18, 95% CI: 1.15–4.12), and recessive model (OR = 1.86, 95% CI: 1.09–3.20), with robust findings according to sensitivity analyses. However, subgroup analyses did not further identify the susceptibility to idiopathic male infertility in all comparisons. Funnel plot inspections did not reveal evidence of publication bias.</p><p>Conclusions</p><p>The current meta-analysis provides evidence of a significant association between CYP1A1 3801T>C polymorphism and idiopathic male infertility risk. Considering the limitation inherited from the eligible studies, further confirmation in large-scale and well-designed studies is needed.</p></div

Funnel plot for the 3801T>C polymorphism of CYP1A1 under allele comparison in idiopathic male infertility.

<p>The vertical axis represents log (OR), and the horizontal axis refers to the standard error of log (OR). The horizontal line indicates the pooled OR, and the sloping lines indicate the expected 95% CI for a given standard error. The area of each circle represents the contribution of the study to the pooled OR.</p

Flow diagram of study selection and specific reasons for exclusion in the meta-analysis.

<p>Flow diagram of study selection and specific reasons for exclusion in the meta-analysis.</p

Poor Prognosis of Phosphatase of Regenerating Liver 3 Expression in Gastric Cancer: A Meta-Analysis

<div><p>Background</p><p>Overexpression of phosphatase of regenerating liver 3 (PRL-3) has been implicated in gastric cancer (GC) metastasis. Epidemiological studies have evaluated the relationship between PRL-3 expression and prognosis in GC. However, results still remains controversial. In this study, a meta-analysis was performed to evaluate the association of PRL-3 expression with overall survival (OS) and clinicopathological characteristics.</p><p>Methods</p><p>Literature databases were searched to identify eligible studies dated until April 2013. Summary hazard ratios (HRs) or odds ratios (ORs) with 95% confidence interval (95% CI) were calculated to estimate the association.</p><p>Results</p><p>A total of 1380 GC patients from six studies were included in the meta-analysis. Overall, the combined HR estimate for OS in a random-effect model was 1.89 (95% CI = 1.38–2.60; <i>P</i><0.001). Results showed that PRL-3 overexpression was significantly associated with OS, indicating that it may be a biomarker for poor prognosis of GC. Both subgroup and sensitivity analyses further identified the prognostic role of PRL-3 expression in GC patients. Moreover, PRL-3 overexpression was significantly associated with tumor stage (OR = 2.25; 95% CI = 1.63–3.12; <i>P</i><0.001), depth of invasion (OR = 2.03; 95% CI = 1.38–2.98; <i>P</i><0.001), vascular invasion (OR = 2.52; 95% CI = 1.79–3.56; <i>P</i><0.001), lymphatic invasion (OR = 3.74; 95% CI = 2.49–5.63; <i>P</i><0.001), and lymph node metastasis (OR = 4.56; 95% CI = 2.37–8.76; <i>P</i><0.001). However, when age, sex, tumor size, and tumor differentiation were considered, no obvious association was observed.</p><p>Conclusions</p><p>This meta-analysis reveals significant association of PRL-3 overexpression with OS and some clinicopathological features in GC. PRL-3 may be a predicative factor of poor prognosis and aggressive tumor behavior in GC patients.</p></div

Meta-analysis of PRL-3 overexpression and prognosis in gastric cancer patients.

<p>All pooled <i>HR</i><b><i>s</i></b> were derived from random-effect model.</p><p><i>P</i>_h<i>P</i>-value for heterogeneity based on <b><i>Q</i></b> test.</p><p><i>P P</i>-value for statistical significance based on <b><i>Z</i></b> test.</p

Results of meta-analysis for 3801T>C polymorphism of CYP1A1 and idiopathic male infertility risk.

<p><i>P_h P</i> value for heterogeneity based on Q test. All pooled ORs were derived from random-effects model except for cells marked with (fixed ^F).</p

Main characteristic of 6 eligible studies enrolled in this meta-analysis.

<p><i>NR</i> data were not reported, <i>NS</i> not significant, <i>ISH</i> in situ hybridization, <i>IHC</i> immunohistochemistry,</p>a<p>directly extracted from original data,</p>b<p>extrapolated from survival curve.</p

Results of Egger's test and Begg's test.

<p>Results of Egger's test and Begg's test.</p

CAYP1A1 3801T >C genotype distribution and allele frequencies in cases and controls.

<p><i>HB</i> hospital based, <i>PCR-RFLP</i> polymerase chain reaction-restriction fragment length polymorphism, <i>MAF</i> minor allele frequency, <i>HWE</i> Hardy–Weinberg equilibrium,</p>a<p>P value for HWE in control group.</p

Flow diagram for study selection and specific reasons for exclusion in the meta-analysis.

<p>Flow diagram for study selection and specific reasons for exclusion in the meta-analysis.</p