For the current analysis, we have focused on the 853 patients who consented to plasma and serum collection, incorporating eight clinical predictors of OS from our previous model: site of metastasis disease (bone metastases only (DS2), any visceral metastases (DS3)), opioid analgesic use (PAIN), Eastern Cooperative Oncology Group performance status (ECOG), LDH > 1 upper limit of normal (LDH.High), albumin (ALB), hemoglobin (HGB), alkaline phosphatase (ALKPHOS), and prostate-specific antigen (PSA) [44]. Here, KLK3 is linked to metastasis.