B7-H1 up-regulated expression in human pancreatic carcinoma tissue associates with tumor progression

Abstract

Aberrant tumor cell B7-H1 expression, a member of B7 family that can predominantly stimulate interleukin 10 (IL-10) products, contributed to the tumor immune evasion and tumor progression. This study was designed to investigate the expression of B7-H1 and IL-10 in normal pancreas tissues and pancreatic carcinoma samples, and to evaluate clinical significance of B7-H1 expression in pancreatic carcinoma. First, the B7-H1 and IL-10 expression in 40 pancreatic carcinoma samples and 8 healthy pancreas specimens using reverse transcription-PCR (RT-PCR) and western-blotting was detected. Localization of B7-H1 and IL-10 was confirmed by immunohistochemical (IHC) staining. Next, the association between B7-H1 expression and tumor differentiation and tumor stage was analyzed. Finally, the correlation between tumor-associated B7-H1 and IL-10 was evaluated. Pancreatic carcinoma samples demonstrated the up-regulated expression of B7-H1 and IL-10 at mRNA and protein level compared with normal pancreas tissues. IHC staining revealed that B7-H1 and IL-10 was almost localized in tumor cells. Analysis of relationship between B7-H1 and tumor clinicopathological characteristics showed that B7-H1 expression was significantly associated with poor tumor differentiation (P < 0.01) and advanced tumor stage (P < 0.01). Meanwhile, tumor-associated B7-H1 expression was also correlated with IL-10 products (P < 0.01, R (2) = 0.6985, mRNA level; P < 0.01, R (2) = 0.7236, protein level) in tumor cells. Our findings for the first time demonstrated up-regulated B7-H1 expression in human pancreatic carcinoma tissues, which might play a role in tumor progression and invasiveness. This expression seemed to be related to the ability of B7-H1 to promoting IL-10 secretion.