Amongst GFAP-expressing cells, we observed a ~30% increase in the fraction that were vimentin-positive (Fig. 7H, p = 0.036, 2-tailed paired t-test, n = 3 tissue samples from different patients), suggesting that even in low-grade gliomas, a vast majority of tumor cells may be aggressive. The gene discussed is GFAP; the disease is central nervous system cancer.