The meta and bioinformatics analysis of GRP78 expression in gastric cancer

GRP78 is a molecular chaperone located in endoplasmic reticulum, and induces folding and assembly of newly-synthesized proteins, proteasome degradation of aberrant proteins, and translocation of secretory proteins, autophagy, and epithelial-mesenchymal transition. We performed a systematic meta- and bioinformatics analysis through multiple online databases up to March 14, 2017. It was found that up-regulated GRP78 expression in gastric cancer, compared with normal mucosa at both protein and mRNA levels (p < 0.05). GRP78 expression was positively correlated with depth of invasion, TNM staging and dedifferentiation of gastric cancer (p < 0.05), while its mRNA expression was negatively correlated with depth of invasion, histological grading and dedifferentiation (p < 0.05). A positive association between GRP78 expression and unfavorable overall survival was found in patients with gastric cancer (p < 0.005). A higher GRP78 mRNA expression was positively correlated with overall and progression-free survival rates of all cancer patients, even stratified by aggressive parameters, or as an independent factor (p < 0.05). These findings indicated that GRP78 expression might be employed as a potential marker to indicate gastric carcinogenesis and subsequent progression, even prognosis.