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Neuro Oncol. 2009 Dec;11(6):757-66. doi: 10.1215/15228517-2009-014.

B7-H1 is correlated with malignancy-grade gliomas but is not expressed exclusively on tumor stem-like cells.

Author information

1
Department of Neurosurgery, Huashan Hospital, Fudan University, Shanghai 200040, China.

Abstract

Human glioblastoma is well known for its capacity to interfere with effective antitumor immune responses. B7-H1 is the third member of the B7 family that plays important roles in tumor immune evasion. Recent studies have shown that brain tumor stem-like cells (TSCs) contribute to tumorigenesis and radioresistance. However, the relationship between B7-H1 and the clinical behavior of brain TSCs remains unclear. In the present study, we report that B7-H1 is correlated with the malignancy grade of astrocyte tumors. B7-H1 was significantly upregulated at the growing edge of the tumors. Immunostaining and flow cytometric analysis indicate that B7-H1 was expressed primarily by Ki67-negative tumor cells. In vitro, tumors cultured under medium favoring the growth of neural stem cells were able to form spheres, along with expression of neural stem/progenitor cell markers. These cells were able to differentiate into different neural lineages when cultured in differentiation medium, indicating that these cells have TSC characteristics. We also found that B7-H1 was expressed, but not exclusively on CD133-positive stem cells. Interestingly, we found that CD133-negative tumor cells also had the capacity to form brain tumors. Our data establish a correlation between the expression of the negative costimulatory molecule B7-H1 and the malignancy grade of human gliomas, suggesting that B7-H1 may be a novel tumor marker and target for therapy, although it is not expressed exclusively on brain TSCs.

PMID:
19264916
PMCID:
PMC2802396
DOI:
10.1215/15228517-2009-014
[Indexed for MEDLINE]
Free PMC Article

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