ABCB1 and prostate carcinoma: MDR-1/P-gp is expressed by both our DU145RD and 22Rv1RD cells but is undetectable in the parent cells, implicating it as involved in the acquired docetaxel-resistance (this observation is somewhat in keeping with the clinical situation where the majority of prostate cancers are MDR-1/P-gp-positive [26]).