SLCO4A1 and cancer: Interestingly, a previous study suggested a possible link between hypoxia and the expression of OATP1B3 in cancer cells,37 and others found an upregulation of SLCO4A1 gene expression in hypoxia in neuroblastoma patients.38,39 Despite these findings, an understanding of the tissue-specific context of this signaling axis, particularly in GBM, is lacking.