However, Fujishiro et al. found that there is a significant upregulation of FECH and ABCG2 in human GBM cell line A172-derived CSCs, suggesting that glioma CSCs could be targeted by the combination of 5-ALA-PDD/PDT with FECH or ABCG2 inhibitors [70]. This evidence concerns the gene ABCG2 and glioma.