SLCO1B3 and neoplasm: OATP1B3 is an influx transporter of particular interest, because it is frequently overexpressed in CNPC and metastatic CRPC (mCRPC) compared to normal adjacent prostate.18–20 Moreover, OATP1B3 seems to have a dual character in PCa, while SLCO1B3 overexpression has been linked to testosterone uptake; downregulation was correlated with docetaxel resistance in vivo.13,21 We previously showed that cabazitaxel efficacy and tumour accumulation are also impaired by testosterone, indicating that testosterone impacts taxane efficacy in general.8