We report the case of a 72-year-old male with high-risk prostate adenocarcinoma (Gleason 4+5=9) and extensive bone metastases, who demonstrated partial radiologic and metabolic response on prostate-specific membrane antigen PET/CT and single-photon emission CT/CT imaging following systemic therapy while simultaneously exhibiting rising prostate-specific antigen levels and elevated systemic inflammatory markers. This evidence concerns the gene KLK3 and prostate adenocarcinoma.