Annexin A7 expression is downregulated in late-stage gastric cancer and is negatively correlated with the differentiation grade and apoptosis rate

Annexin A7 is a member of the Annexin A family, which participates in various biological processes. Accumulating evidence has demonstrated that Annexin A7 serves an important role in tumorigenesis and is dysregulated in multiple types of cancer. However, the role of Annexin A7 in the tumorigenesis of gastric cancer remains to be determined. The present study revealed that Annexin A7 expression is downregulated in late-stage gastric cancer and is negatively correlated with the differentiation grade and apoptosis. There was a significant difference in Annexin A7 mRNA and protein expression in gastric cancer samples with distinct differentiation grades, with the lowest expression being observed in the highly differentiated cases. A terminal deoxynucleotidyl-transferase-mediated dUTP nick end labelling assay demonstrated that the apoptosis indices of highly, moderately and poorly differentiated gastric cancers were 18.12±2.40, 9.73±1.73 and 4.13±0.83%, respectively, with statistical significance (P<0.05). Flow cytometric analysis demonstrated that the apoptosis rates of gastric cancer MKN74, SGC7901 and BGC823 cells were 10.07±1.21, 7.11±1.04 and 4.25±1.02%, respectively, with statistical significance (P<0.05). Spearman's rank correlation analysis revealed that the Annexin A7 mRNA and protein levels were negatively correlated with the differentiation grade of the gastric cancer tissues, while the apoptosis index was positively correlated with the differentiation grade of the gastric cancer tissues. Furthermore, the apoptosis index was negatively correlated with Annexin A7 mRNA and protein expression. Similar associations were observed among Annexin A7 expression, differentiation grades and apoptosis in gastric cancer cell lines. The results of the present study demonstrated that Annexin A7 expression is downregulated, while apoptosis is upregulated, with the progression of gastric adenocarcinoma. These observations suggested that Annexin A7 may inhibit apoptosis during tumorigenesis and that it is a potential biomarker for the diagnosis, prognosis and treatment of gastric adenocarcinoma.