HSPB1 and astrocytoma (excluding glioblastoma): Additionally, a stepwise increase of HSPB1 mRNA expression was observed in parallel to the increase in malignancy mainly in diffusely infiltrative astrocytomas from grade II to IV (p <0.05 to p <0.0001, Kruskal Wallis and Dunn's tests), and when these results were plotted on ROC curves, an increasing value of the area in parallel to the increment of the malignancy was observed (Fig. 4a), strongly suggesting that HSPB1 expression level as an indicator of tumor progression.