Through introducing Nf1 and p53 mutations into MADM, Liu et al. established the MADM glioma model and found oligodendrocyte progenitor cells (OPCs) are the cell-of-origin of glioma via quantifying the green (mutant)/red (wildtype) cell number ratio during gliomagenesis (78). The gene discussed is TP53; the disease is central nervous system cancer.