Programmed death-ligand 1 (PD-L1) may play a role in malignant glioma infiltration

Infiltration is the main cause of death of malignant glioma patients. However, the mechanisms of the infiltration in the development of brain cancer (glioblastoma multiforme) are not completely understood. Here, we hypothesized that, in the development of human brain cancer, infiltration is primarily due to differentiated cancer cells and that the cell surface molecule programmed death-ligand 1 (PD-L1) may play an important role in brain tumor infiltration. PD-L1 is highly expressed in differentiated glioma cells in comparison to undifferentiated ones. As PD-L1 has both pro-survival and immunoinhibitory functions in tumor cells, the potential role of PD-L1 in tumor propagation suggest a new therapeutic target for preventing glioma infiltration and recurrence. (C) 2015 Elsevier Ltd. All rights reserved.