Although first-line treatments, including androgen deprivation therapy for metastatic hormone-sensitive prostate cancer (mHSPC), are initially highly effective in decreasing the levels of the standard indicator of PCa progression, namely, prostate-specific antigen (PSA), and in shrinking tumors, therapeutic resistance is almost universal, and the disease often progresses to metastatic castration-resistant prostate cancer (mCRPC). The gene discussed is KLK3; the disease is posterior cortical atrophy.