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.
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.