Background: Neuroendocrine (NE) expression in prostatic adenocarcinomas (PACs) has been related to an adverse clinical course, but the reported data are not unequivocal.
Methods: We immunostained a series of 64 PACs with three monoclonal antibodies raised against chromogranin A (CgA), chromogranin B (CgB), and secretogranin II (SgII). The patients were followed up for 18-88 months (mean 43 months, standard deviation +/- 20 months); 58 of them received preoperative androgen deprivation therapy for 3-6 months.
Results: Of the 64 PACs under study, 39 (approximately 61%) were immunoreactive to CgA, 51 (approximately 80%) to CgB, and 38 (approximately 59%) to SgII. We found a strict correlation between pronounced neuroendocrine differentiation and the most poorly differentiated tumors (P = 0.01 for CgA, P = 0.03 for CgB, and P = 0.05 for SgII), and relationship (approaching statistical significance only for CgB, P = 0.07) between Cgs/Sg expression and advanced (C and D) clinical stage. However, we failed to detect any correlation between chromogranin expression and clinical outcome.
Conclusions: These results suggest that NE differentiation is a frequent event in PACs, especially in the most poorly differentiated. Nevertheless, as Cgs/Sg expression is not clearly related to advanced clinical stage and poor prognosis, our findings suggest that clinical staging and grading, rather than NE differentiation, remain the most powerful prognostic indicators in PACs.