ALDH1A1 and glioblastoma: In terms of different grades of glioma, cytoplasmic staining of ALDH1 was significantly increased in grade IV GBM compared with that in grade II glioma (p < 0.0001) and grade III astrocytoma (p < 0.01) (Fig. 7D left), while nuclear staining of ALDH1 was significantly increased in grade IV GBM compared with that of grade II gliomas (p < 0.05) (Fig. 7D right).