Survivin -31G>C polymorphism and gastrointestinal tract cancer risk: a meta-analysis

Abstract

Background: Emerging evidence showed that common functional -31G>C polymorphism (rs9904341 G>C) in the promoter region of the survivin gene is involved in the regulation of survivin expression, thus increasing an individual's susceptibility to gastrointestinal tract (GIT) cancer; but individually published results are inconclusive. The aim of this systematic review and meta-analysis was to derive a more precise estimation of the association between survivin -31G>C polymorphism and GIT cancer risk.

Methods: A literature search of PubMed, Embase, Web of Science and CBM databases was conducted from inception through July 1st, 2012. Crude odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of association.

Results: Nine case-control studies were included with a total of 2,231 GIT cancer cases and 2,287 healthy controls. The results indicated that survivin -31G>C polymorphism was associated with increased risk of GIT cancer. In the stratified analysis by cancer types, significant associations were observed between survivin -31G>C polymorphism and increased risk of colorectal and gastric cancers. However, the lack of association of survivin -31G>C polymorphism with esophageal cancer risk may be due to a lack of a sufficient number of eligible studies and the influence of different genetic and environmental factors.

Conclusion: Results from the current meta-analysis suggests that survivin -31G>C polymorphism might increase the risk of GIT cancer, especially among gastric and colorectal cancers.

Figure 1. Flow chart of literature search and study selection.

Figure 2. Forest plot of ORs with a random-effects model for associations between survivin −31G>C polymorphism and gastrointestinal tract cancer risk under dominant model (CC+GC vs. GG).

Figure 3. Subgroup analysis by cancer type of ORs with a random-effects model for associations between survivin −31G>C polymorphism and gastrointestinal tract cancer risk under dominant model (CC+GC vs. GG).

Figure 4. Subgroup analysis by ethnicity of ORs with a random-effects model for associations between survivin −31G>C polymorphism and gastrointestinal tract cancer risk under dominant model (CC+GC vs. GG).

Figure 5. Sensitivity analysis of the summary odds ratio coefficients on the association between survivin −31G>C polymorphism and gastrointestinal tract cancer risk under dominant model (CC+GC vs. GG).

Results were computed by omitting each study in turn. Meta-analysis random-effects estimates (exponential form) were used. The two ends of the dotted lines represent the 95% CI.

Figure 6. Begger’s funnel plot of publication bias in selection of studies on the survivin −31G>C polymorphism under dominant model (CC+GC vs. GG).

Each point represents a separate study for the indicated association. Log[OR], natural logarithm of OR. Horizontal line, mean magnitude of the effect.