HIF1α promoted drug resistance in human medulloblastoma by inhibition of CYP2B6, CYP3A4 and CYP3A5 expression, which in turn resulted in decreased conversion of CPA and IFA into their active forms and thus to diminished cytotoxicity (Valencia-Cervantes et al., 2019). This evidence concerns the gene CYP3A4 and medulloblastoma.