Since the enzymes responsible for the metabolization of oxcarbazepine (AKR1C1, AKR1C2, AKR1C3, and AKR1C4) are highly expressed in hepatocytes but not in glioma cells, we expect only marginal transformation to MHD in our in vitro proliferation assay [17]. This evidence concerns the gene AKR1C4 and central nervous system cancer.