400 patients will be enrolled and divided into 3 cohorts: Cohort A: patients with high risk localized prostate cancer (PC) defined as >cT3 or PSA > 20 ng/mL or presence of ECE or SVI at mpMRI;

Cohort B: patients with de novo metastatic hormone sensitive prostate cancer (mHSPC);

Cohort C: patients with metastatic castration resistant prostate cancer (mCRPC) progressing on a standard treatment.

In this study 150 patients will be enrolled in cohort A, 100 patients in cohort B and 100-150 patients in Cohort C.

Considering the known frequency of DDR and MMR germline/somatic alterations, it is expected to see:

• 15-23 patients with germline/somatic DDR defects and 5-7 MMR alterations in cohort A;
• 20-25 patients with germline/somatic DDR defects and 5-7 MMR alterations in cohort B;
• 25-35 patients with germline/somatic DDR defects and 7-10 MMR alterations in cohort C.

Patients within Cohort A will be followed up with PSA every 3 months for 3 years and early scans. They will also receive a blood sample for ctDNA/CTC before (when feasible) and after radical treatment, 6 months and 12 months (if not progressed), at time of PSA or radiological progression;

Patients within Cohort B will be followed up with PSA and scans every 3 months. They will also receive a blood sample before (when feasible) or after the start of systemic treatment, 6 months and 12 months (if not progressed), at time of PSA or radiological progression.

Patients within Cohort C will be followed up with PSA monthly and scans every 3 month. They will also receive a blood sample for ctDNA/CTC before (when feasible) or after the start of systemic treatment, 6 months and 12 months (if not progressed), at time of PSA or radiological progression.

Inclusion Criteria:

• Age > 18 years
• Diagnosis of prostate cancer as indicated below:

Cohort A: patients with high risk localized prostate cancer (defined as >cT3 or PSA > 20 ng/mL or presence of ECE or SVIat mpMRI), with tissue available from diagnostic biopsy/ prostatectomy undergoing or who underwent curative treatment (prostatectomy/ radical radiotherapy) but have not started a FU pathway.

Cohort B: patients with de novo metastatic hormone sensitive prostate cancer (mHSPC) with tissue available from diagnostic biopsy of the primary and when possiblepossible, from a metastatic site. Patients must either have not started a standard treatment or have started for not longer than 3 months.

Cohort C: patients with metastatic castration resistant prostate cancer tissue (mCRPC) progressing on a standard treatment with available from biopsy of a metastatic site, and when possiblepossible, from the primary.

• Ability to understand and consent to informed consent;
• Patient must be compliant with receiving a biopsy of the metastatic site (cohort C) and with FU assessments schedule

Exclusion Criteria:

• Patients not willing to comply with study's procedures or fulfilling the inclusion criteria.

Cohort A: patients with high risk localized prostate cancer (PC) defined as >cT3 or PSA > 20 ng/mL or presence of ECE or SVI at mpMRI; Cohort B: patients with de novo metastatic hormone sensitive prostate cancer (mHSPC); Cohort C: patients with metastatic castration resistant prostate cancer (mCRPC) progressing on a standard treatment.