ID2 and glioma: Specifically, mRNA levels of ID1 (colon/glioblastoma CSC-regulation [13], 2.5-fold), ID2 (glioma stem cell regulation [13], 3.2-fold), ID3 (colon/glioma CSC-regulation [13], 2.9-fold), ALDH7A1 (prostate CSC marker/metastasis [14], 2-fold) were significantly downregulated and KLF9 (glioblastoma stem cell inhibitor [15], 1.5-fold) was significantly upregulated in HCT116 p53-null cells upon 48 hour ONC201 treatment (Table 1), indicative of potential anti-CSC effects in these solid tumors.