SOX2 and central nervous system cancer: To further validate these findings, we quantified total cellularity and the IHC labeling indices SOX2, NeuN, CD68, and Ki67 in 45 recurrent and primary glioma samples (Fig. 6f) and found that total cellularity was highest in cluster C, which also had the highest abundance of SOX2+ and Ki67+ cells, while cluster A had the highest abundance of NeuN+ cells, and Cluster B had the highest abundance of CD68 + cells.