Stephanie van Hoppe

170 Chapter 7 the blood-brain barrier of patients in a chronic setting, as would be required for clinical treatment with most targeted anticancer drugs, should be carefully assessed. Based on our experience with knockout mouse models, unpredictable (CNS) toxicity of drugs, pesticides and even some food components to which such patients will inevitably be exposed might emerge. Even in cases where we did not see any toxicity in mice, this cannot always be simply translated to humans. Therefore, whether this inhibition option could be effective and plausible in the clinic remains to be further investigated. As suggested before, we think it would be better if pharmaceutical companies would give additional weight to developing targeted anticancer drugs that are hardly or preferably not at all transported by ABCB1 and ABCG2. As illustrated (amongst others) in this thesis, the tools to help achieving that goal are in principle available.