Clinicopathological and prognostic significance of HER2 overexpression in gastric cancer: a meta-analysis of the literature.

Human epidermal growth factor receptor 2 (HER2) plays an important role in the aggressiveness and progression of gastric cancer. With the publication of trial results, we conducted a meta-analysis to investigate its prognostic significance for patients with gastric cancer. PubMed, Ovid, Web of Science, and Cochrane databases were searched. Statistical analysis was carried out by STATA version 12.0 software. The Newcastle-Ottawa scale was used to assess the quality of evidence. Fifteen studies involving 5,290 patients met the inclusion criteria. The results showed that HER2 overexpression was significantly associated with patients' overall survival (HR = 1.56, 95% confidence interval (CI) 1.05-2.07; Z = 6.03; P = 0.000). The results also suggested that HER2 overexpression was associated with Bormann type (odds ratio (OR) = 1.76, 95% CI 1.19-2.59; Z = 2.85; P = 0.004), tumor differentiation (OR = 3.14, 95% CI 1.91-5.17; Z = 4.49; P = 0.000), Lauren's classification (OR = 6.25, 95% CI 4.29-9.10; Z = 9.54; P = 0.000), lymph node metastasis (OR = 1.43, 95% CI 1.15-1.77; Z = 3.23; P = 0.001), venous invasion (OR = 1.69, 95% CI 1.15-2.48; Z = 2.67; P = 0.008), and lymphovascular invasion (OR = 1.57, 95% CI 1.21-2.04; Z = 3.4; P = 0.001). However, it had no correlation with tumor size, depth of invasion, and tumor stage. This study showed that HER2 overexpression had an unfavorable prognostic role for patients with gastric cancer. HER2-positive expression was associated with Bormann type, Lauren's classification, tumor differentiation, lymph node status, venous invasion, and lymphovascular invasion.