To determine the clinical significance and biological role of AP4 in human CRPC, we detected AP4 expression in human PCa tissues and found that AP4 expression was increased in PCa tissues (n=136) and CRPC tissues (n=8) collected from patients with urinary obstruction compared with paired normal prostate tissues (n=136) and paired androgen-sensitive PCa (ASPC) tissues (n=8) (Figures 7a and b,Table 1 and Supplementary Table S3). This evidence concerns the gene TFAP4 and posterior cortical atrophy.