ABCG2 and glioma: Gene regulation by ABCG2 was mediated via diverse mechanisms in a cell type-dependent manner, frequently involving the transcription factor MEF. In addition to demonstrating a novel and active role for the stem cell marker ABCG2 in driving parts of the glioma stem cell phenotype, our findings emphasize the need to separate the various stem cell characteristics that are usually considered as a collective unit.