Prohibitin: a potential biomarker for tissue-based detection of gastric cancer

Background. Prohibitin (PHB) was found to be overexpressed in breast cancer and thus is suggested as a biomarker in that disease. A few studies have investigated the PHB expression pattern in gastric cancer by two-dimensional gel electrophoresis. Uncertainties still existed on whether PHB expression could indicate the differentiation and apoptosis degree of gastric cancer and whether PHB protein as well as anti-PHB antibody could be a biomarker in the serum of the gastric cancer patient. In this study, the expression levels of PHB protein and mRNA of the tissues as well as PHB antigen and anti-PHB antibody in serum of patients with gastric cancer were systemically examined. Methods. Immunohistochemistry and real-time PCR were used to detect expression levels of PHB protein and mRNA in gastric cancer tissues. Recombinant PHB antigen was identified by Western blotting. The expression of PHB antigen and anti-PHB antibody was investigated by ELISA and TRFIA. Bcl-2 expression was examined by immunohistochemistry. Results. By immunohistochemistry and real-time PCR analyses, PHB protein and mRNA were both overexpressed in gastric cancer tissues compared to adjacent normal gastric tissues (P < 0.01). Moreover, an elevated PHB expression pattern paralleled the differentiation degree and Bcl-2 protein expression in gastric cancer. However, no significant differences of PHB protein and anti-PHB antibody expression were detected in serum of gastric cancer patients and that of healthy volunteers. Conclusions. These results indicated that PHB could be a potential diagnostic and differentiation biomarker of gastric cancer for tissue-based detection by immunohistochemistry and real-time PCR, but not for serum-based detection.