Overexpression of B7-H1 (PD-L1) significantly associates with tumor grade and postoperative prognosis in human urothelial cancers
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- Nakanishi, J., Wada, Y., Matsumoto, K. et al. Cancer Immunol Immunother (2007) 56: 1173. doi:10.1007/s00262-006-0266-z
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The programmed death-1 (PD-1)/B7-H1 (also called PD-L1) pathway negatively regulates T cell activation and has been suggested to play an important role in regulating antitumor host immunity. To investigate the clinical significance of B7-H1 expression to the tumor grade and postoperative prognosis of patients with urothelial cancer, we analyzed the relationship between B7-H1 expression and various clinicopathological features and postoperative prognosis.
Sixty-five urothelial cancer cases were examined. B7-H1 expression in tumors and the numbers and phenotypes of tumor-infiltrating lymphocytes were evaluated by immunohistochemistry and flow cytometry.
A substantial expression of B7-H1 was observed in all urothelial cancers investigated. Tumor specimens from patients with higher WHO grade or primary tumor classifications showed significantly higher percentages of tumor-associated B7-H1. Tumor-associated B7-H1 expression was significantly associated with a high frequency of postoperative recurrence and poor survival rate. Furthermore, multivariate analysis indicated that tumor-associated B7-H1 was more significant prognostic factor than WHO grade.
Our results demonstrate that the aberrant expression of B7-H1 in urothelial cancer is associated with aggressive tumors, suggesting a regulatory role of tumor-associated B7-H1 in antitumor immunity. Therefore, the manipulation of tumor-associated B7-H1 may become a beneficial target for immunotherapy in human urothelial cancer.