B7-H1 expression associates with tumor invasion and predicts patient's survival in human esophageal cancer

B7-H1, an important member of the B7-CD28 super family, has been reported to play an important role in regulation of T-cell mediated anti-tumor response, and also has effect in the biological characteristics of the tumor cells themselves. The bulk of data indicate that cancer immunotherapy targeting the molecule B7-H1 recently has sparked growing interest. We have previously reported that higher expression of B7-H1 in human gastric cancer significantly associated with tumor size, invasion, nodal metastasis, survival and the density of infiltrating Foxp3+ Tregs. In the present study, we used tissue microarray to further study B7-H1 expression in human esophageal cancer tissues and its clinical significance. We found that positive membranous B7-H1 expression could be found in some human esophageal cancer cell lines, and both membranous/cytoplasm and nuclear staining of B7-H1 could be found in esophageal cancer tissues. We demonstrated that the membranous/cytoplasm B7-H1 expression in human esophageal cancer tissues was significantly correlated with tumor invasion depth (P = 0.0261), whereas it was not correlated with patient's gender, age, tumor size, nodal metastasis, distant metastasis and TNM stage. The survival analysis showed that the overall survival of the patients with positive B7-H1 membrane/cytoplasm expression was significantly poorer than that of the patients with negative B7-H1 membrane/cytoplasm expression (Hazard ratio = 2.157, 95% CI: 1.017-4.577, P = 0.0452). Moreover, we also found that the nuclear B7-H1 expression in human esophageal cancer tissues was significantly correlated with tumor invasion depth (P = 0.0331), whereas it was not correlated with other parameters. The log-rank survival analysis showed that there was no statistically significant difference in prognosis between the patients with positive nuclear B7-H1 staining and the patients with negative nuclear B7-H1 staining (P = 0.6755). Thus, our data showed that B7-H1 can serve as a prognostic predictor for human esophageal cancer, and also could be an important therapeutic target for the immune therapy against this malignancy.