PGP and prostate cancer: Interestingly, cabazitaxel, a taxane derivative with poor affinity for another drug-efflux pump protein, P-glycoprotein 1 (P-gp, also known as multidrug resistance protein 1 and ABCB1), was recently approved for use in patients with castration-resistant prostate cancer who had previously failed docetaxel-based regimens [30].