Clinical significance of EBP50 overexpression assessed by quantum dot analysis in gastric cancer

Ezrin-radixin-moesin-binding phosphoprotein 50 (EBP50) is a postsynaptic density-95/disc-large/zonula occludens-1 (PDZ) homologous domain-containing protein that is involved in cell signaling. EBP50 regulates cell apoptosis, proliferation and invasion. In the present study, the prognostic impact factor of EBP50 expression was evaluated using a quantum dot (QD)-based assay and immunohistochemistry (IHC). The EBP50 protein expression in gastric cancer (GC) tissues was evaluated using IHC and QD-IHC. The study included 101 patients with GC (29 females and 72 males, aged 24-81 years), diagnosed and treated at the General Surgery Department of Renmin Hospital of Wuhan University (Wuhan, China) between 2000 and 2005. The survival rate was calculated using the Kaplan-Meier method and log-rank tests. IHC and QD analyses of 101 GC tissue specimens revealed that EBP50-positive tumor cells were frequently present in GC. Increased EBP50 immunostaining was observed in 63 specimens (62.4%). The EBP50 expression levels were correlated with increased tumor size and the male gender. EBP50 was well distributed in the cytoplasm and nuclei of the GC cells. However, EBP50 protein expression exhibited no correlation with age, differentiation, stage or lymph node metastasis. There were no associations between the expression of EBP50 and the mean survival rates (IHC, 50.5 vs. 58.1 months, P>0.05; QD, 55.4 vs. 63.2 months, P>0.05). These findings suggest that EBP50 protein expression is not correlated with the prognosis of patients with GC. QD-IHC and IHC have similar advantages for the detection of EBP50 protein expression.