Identification of biomarkers (Circulating Tumor Cells (CTC), free DNA, Stem Cells and EMT-related antigens) that may be predictive of outcome of activity of cabazitaxel treatment in castration-resistant prostate cancer.

Circulating Tumor Cells, free DNA, Stem Cells and EMT-related antigens as biomarkers of activity of cabazitaxel in castration-resistant prostate cancer

Primary objectives: To evaluate the prognostic role of response of the copy number of androgen receptor (AR) and Phosphatase and tensin homolog (PTEN) and AR-V7 and other gene expression biomarkers in CTC and the investigators will compare these results with those obtained in plasma cell free DNA and RNA.

Eligible patients must have histologically or cytologically confirmed prostate cancer or unequivocal increased PSA . Metastatic and/or inoperable disease and received prior therapy with docetaxel and candidate to cabazitaxel treatment.

All patients receive cabazitaxel at standard schedule 25 mg/m2 q21. Blood sample will be collected for CTC evaluation at baseline, after the first cycle of therapy (optional), at first radiological evaluation (after 3 months), at disease progression (optional) or after 9-12 months of treatment for patients who did not show disease progression (optional). Disease progression defined according to Prostate Cancer Working Group 2 (PCWG2) criteria. On blood samples from Castration-Resistant Prostate Cancer (CRPC) patients the investigators will investigate the presence of the previously presented CTC, DNA and RNA free markers.

As an option, it will be possible to require a sample of the tumor collected during prostate surgery or during the biopsy.

All patients will be treated and monitored according to the local clinical practice. No additional procedures/patient visits in comparison with the usual clinical practice are planned for the study.

Inclusion Criteria:

1. Ability to understand and the willingness to sign a written informed consent document
2. Male aged >18 years with metastatic castration-resistant disease with documented clinical (imaging) and/or biochemical progression (PSA increasing values) during or after a previous docetaxel-based chemotherapy
3. Patients must have metastatic and/or inoperable disease
4. Patients must have received prior therapy docetaxel based and must be candidate to cabazitaxel
5. Life expectancy of greater than 3 months
6. Eastern Cooperative Oncology Group (ECOG) performance status <2

Exclusion Criteria:

1. Participants who are unable to provide informed consent
2. Participation in another clinical trial

Patients with castration-resistant prostate cancer