Some resistant cancer cells (such as PC3-TxR, a prostate cancer cells resistant to docetaxel) are known to be capable of over-expressing P-glycoprotein (P-gp), an efflux pump capable of pumping the active drug from intracellular site to extracellular site and thus decrease drug intracellular concentration. The gene discussed is ABCB1; the disease is Familial prostate cancer.