HSPB1 and glioblastoma: Moreover, when the overall survival times of GBM cases presenting ±3 fold cut off value of HSPB1 expression level calculated based on the ROC curve (3×7.76 = 23.28) were compared to those presenting HSPB1 expression level < 23.28, it resulted in a Kaplan-Meier curve with log rank of 0.007 (Fig. 4b).