Clinical importance of B7-H3 expression in human pancreatic cancer

BACKGROUND: B7-H3 is a new member of the B7 ligand family and regulates T-cell responses in various conditions. However, the role of B7-H3 in tumour immunity is largely unknown. The purpose of this study was to evaluate the clinical significance of B7-H3 expression in human pancreatic cancer and the therapeutic potential for cancer immunotherapy. METHODS: We investigated B7-H3 expression in 59 patients with pancreatic cancer by immunohistochemistry and real-time PCR. Furthermore, we examined the anti-tumour effect of B7-H3-blocking monoclonal antibody in vivo in a murine pancreatic cancer model. RESULTS: Tumour-related B7-H3 expression was abundant in most human pancreatic cancer tissues and was significantly higher compared with that in non-cancer tissue or normal pancreas. Moreover, its expression was significantly more intense in cases with lymph node metastasis and advanced pathological stage. B7-H3 blockade promoted CD8(+) T-cell infiltration into the tumour and induced a substantial anti-tumour effect on murine pancreatic cancer. In addition, the combination of gemcitabine with B7-H3 blockade showed a synergistic anti-tumour effect without overt toxicity. CONCLUSION: Our data show for the first time that B7-H3 may have a critical role in pancreatic cancer and provide the rationale for developing a novel cancer immunotherapy against this fatal disease. British Journal of Cancer (2009) 101, 1709-1716. doi: 10.1038/sj.bjc.6605375 www.bjcancer.com Published online 20 October 2009 (C) 2009 Cancer Research UK