In GBM, bulk RNA-sequencing has revealed the transcriptional expression of multiple OATP subtypes within the tumor parenchyma.21,22 Specifically, Bronger et al21 investigated the mRNA expression of ABCC drug efflux pumps and OATPs in human gliomas and the blood–tumor barrier, revealing the expression of SLCO1A2, 1C1, 2B1 and 4A1 in human glioma samples. Here, SLCO1A2 is linked to neoplasm.