Hypoxia-inducible factor 1α in regulation of programmed death: Ligand 1 in glioma under hypoxia microenvironment.

103Background: Glioma is a highly lethal tumor that is known for its immune inhibitory capabilities. Despite great progress in treatment modalities, the median survival time of high-grade gliomas patients is only about 11.1 months. Gliomas are aberrantly expressed programmed death–ligand 1 (PD-L1) which results in tumor-induced immune suppression. Hypoxia is well known to induce aggressiveness, promotes tumor progression and resistance to chemotherapy and radiotherapy. Recently, studies have indicated that hypoxia play a prominent role in tumor immune escape. The aim of the study was to explore the relationship between PD-L1 and hypoxia inducible factor 1α (HIF-1α) and the role in the progression of gliomas. Methods: We adopted immunohistochemistry methods to detect expressions of PD-L1 and HIF-1α in 64 surgical specimens (23 cases for low-grade and 41 cases for high-grade gliomas, respectively). Immunoreactivity was analyzed in association with patients’ clinical characteristics or survival time. Express...