Study of Natural Killer Cells in Patients With Metastatic Prostate Cancer: Relationship With Survival and Response Time to Castration

Inclusion Criteria: 1. Patient with metastatic prostate cancer. 2. Aged of 18 years or more. 3. Patient in period of sensitivity to castration (patient non castrated or castration performed less than 1 year ago) and lack of progression. 4. Patient having signed an informed consent. 5. Patient affiliated to the national "Social Security" regimen or beneficiary of this regimen. Exclusion Criteria: 1. Patient under chemotherapy treatment at the time of sampling 2. Patient under corticotherapy treatment at the time of sampling 3. Patient in emergency situation, adult subject to a measure of legal protection (placed under judicial protection, tutorship, or curatorship), or unable to give consent. 4. Any psychological, familial, sociological or geographical condition potentially hampering compliance with the study medical follow-up 5. Contraindications to study procedure