AR and posterior cortical atrophy: In contrast, the mRNA level of SRD5A3 in the AR-positive xenograft MDA PCa 183 was much lower than that in the AR-negative SCPC xenografts, except for MDA PCa 155 (Fig. 7, bottom), suggesting a loss of AR-negative regulation in the MDA PCa 144 and MDA PCa 146 xenografts.