['In this retrospective study, we assessed chromogranin A (CgA) baseline value as a possible factor associated with poor prognosis in metastatic castration-resistant prostate cancer (CRPC).', 'Thirty-five patients with metastatic CRPC progressing after docetaxel chemotherapy treated with enzalutamide are subdivided into three groups: serum CgA level was normal when <120\u2009ng/ml (group A, n\u2009=\u200910), within three times the upper normal value (UNV) when between 120 and 360 (group B, n\u2009=\u200917), more than three times the UNV when ≥360\u2009ng/ml (group C, n\u2009=\u20098).', 'No correlation was observed in three groups among CgA baseline values and PSA response rates (RR) (P\u2009=\u20090.4648), whereas a significative difference was associated with median progression-free survival (PFS) and overall survival (OS) among three CgA groups (P\u2009=\u20090.0301 and P\u2009=\u20090.0011, respectively). In the multivariate analysis, PSA RR (nonresponsive vs. responsive) and CgA levels (group 3 vs. groups 1\u2009+\u20092) were predictors of OS (P\u2009=\u20090.0029 and P\u2009=\u20090.0025, respectively), whereas they only were not significantly correlated with PFS, even had a borderline significance (P\u2009=\u20090.0628 and P\u2009=\u20090.0772, respectively).'] Is chromogranin A a potential prognostic marker in prostate cancer patients treated with enzalutamide?