IBSP and glioma: In addition, the high BSP expression rate increased with tumor grade: approximately 40% (39.32%, 46/117) grade IV glioma tissue specimens showed high BSP expression while only 13.9% (15/108) grade I–II glioma tissue specimens exhibited high BSP expression (Table S1), a finding further confirmed by our correlation analysis which revealed that high BSP expression correlated with higher tumor grade (P<0.001).