Interestingly, Ascl1-CKO or Olig2-CKO significantly reduced the percentage of tumor cells expressing the other transcription factor at P30 compared to control (Supplementary Fig. 2c, g, k, l), but this reduction was not observed in terminal tumors (Supplementary Fig. 2d, h, k, l). The gene discussed is ASCL1; the disease is neoplasm.