ALDH1A1 and glioblastoma: Notably, ONC201, which is a well‐tolerated compound used in a Phase I/II study for patients with advanced solid tumor (NCT02038699) (NCT02324621),284 has been reported to downregulate CSC‐related genes, including ALDH1A1 and ALDH7A1, and suppress CSCs self‐renewal in CRC, PCa, and GBM cells.285