AR and posterior cortical atrophy: Given mounting data pointing toward the benefits of early initiation of chemotherapy, a test indicating resistance to AR suppression early would provide an opportunity to pivot the therapeutic approach that could potentially result in improved survival.47 We found that genomic regions enriched by GAPF on chrX were almost exclusively seen in PCa plasma cfDNA (Fig. 7I): all four cases with anti-AR therapy resistance and five out of six therapy-sensitive cases.