| Backgrounds The epithelial cell adhesion molecule(EpCAM)is one of the most commonly used markers of cancer stem cells(CSCs),but the clinical and prognostic significance of EpCAM in gastric cancer(GC)remains disputable.Motivated by heterogeneous and inconclusive results,we conducted a systematic review and meta-analysis to systematically summarize and elucidate the association between EpCAM overexpression and GC patients.Methods The Pub Med,Cochrane Library,Medline,Web of Knowledge and the China National Knowledge Infrastructure(CNKI)databases were searched to identify relevant studies(up to April 10,2016)using the following keywords: gastric cancer,EpCAM,CD326,etc.Based on the inclusion and exclusion criteria,which were prepared in advance,two reviewers independently screened the literature,extracted the data,and assessed the methodological qualities of the included studies.The Rev Man 5.3 software was used for the meta-analysis.Fixed-effects or random-effects models were applied depending on the presence of heterogeneity.Sensitivity analysis were performed on significant heterogeneity studies.The pooled odds ratio(ORs)and95% confidence intervals(CIs)were applied to estimate the associations between EpCAM and gastric cancer.The outcomes included gender,age,various clinicopathological features and overall survival.Results A total of 11 case-control studies including 1960 GC patients met our inclusion criteria.The results of the meta-analyses revealed that there were significant differences in EpCAM overexpression related to tumour size [>5 cm vs.?5 cm(OR =2.97,95% CI: 2.13~4.13,P < 0.00001)],the nature of the tissue [gastric cancer vs.control tissue(OR = 80.30,95% CI: 29.21~220.81,P < 0.00001)],lymph node metastasis [positive vs.negative(OR = 2.78,95% CI: 1.23~6.27,P =0.01),and the cumulative 5-year overall survival rate [EpCAM-positive vs.EpCAM-negative(OR =0.54,95% CI:0.29~0.99,P =0.05)].No significant associations were identified between EpCAM overexpression and gender [male vs.female(OR = 0.89,95% CI:0.66~1.19,P =0.43)],age [>60 vs.?60(OR = 1.13,95% CI: 0.58~2.20,P =0.73)],tumour stage [T3~T4 vs.T1~T2(OR = 2.26,95% CI: 0.79~6.45,P =0.13)],distant metastasis [M1 vs.M0(OR = 2.15,95% CI: 0.20~22.69,P =0.52)],TNM stage [?~? vs.I~II(OR = 5.14,95% CI: 0.77~34.37,P =0.09)],Lauren type [intestinal vs.diffuse(OR = 1.18,95% CI: 0.08~16.45,P =0.9)],or differentiation [well/moderate vs.poor(OR = 1.88,95% CI: 0.65~5.41,P =0.24)].However,due to significant heterogeneity in tumor stage,lymph node metastasis,TNM stage,differentiation and Lauren type,we should take these results carefully.Conclusion The meta-analysis demonstrated that the expression of EpCAM in the gastric cancer group was greater than that in the control group.Moreover,EpCAM overexpression was associated with larger tumour size,lymph node metastasis and worse prognosis in gastric cancer.For the relationship between EpCAM and other clinicopathological features,due to heterogeneity,the sensitivity analysis suggests that population factor may be an important source of heterogeneity,and these results should be treated with caution.In conclusion,EpCAM may serve as a new type of gastric cancer marker and prognostic factor,and future studies are needed on a large scale and well designed to further validate the exact relationship between EpCAM and gastric cancer. |
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