ABCB1 and neoplasm: For the castration-induced regression nadir group (i.e., those with the weakest or most unsuccessful castration-induced tumor regression), GSE1, CYP3A5, CTNNB1, CYP3A4, POU5F1, ABCB1, alkaline phosphatase liver/bone/kidney isozyme (ALPL), PROM1/CD133, ABCG2, and SOX2 were concomitantly upregulated.