In leuprolide-treated patients, we found a significant increase in PARP1 activity as reflected in increased PARylation (P = 0.003) compared with biopsies taken from the same patients before castration (Fig. 2c, d), suggesting that PARP1 is activated as a result of androgen deprivation, further strengthening our findings showing that AR regulates HR in PCa. This evidence concerns the gene PARP1 and posterior cortical atrophy.