Specificities of small cell neuroendocrine prostate cancer: Adverse prognostic value of TTF1 expression

To determine whether small cell neuroendocrine prostate cancers (NEPCa) emerging after anti-androgen treatments are different from the rarest cases diagnosed de novo, and to identify effective predictive markers. The expression of markers, androgen receptor (AR) androgen-regulated genes, as well markers aggressiveness, were analyzed by immunohistochemistry on a tissue microarray containing samples 30 sNEPCa, either pure or admixed with conventional PCa, including 14 novo 16 subsequent prior deprivation. Chromogranin A is better marker NE differentiation than synaptophysin in post-treatment NEPCa, 94% 44% positive tumors, respectively, while both equally expressed cases. Despite acquisition phenotype, more half NEPCa AR gene NKX3.1, frequently PCa. TTF1 staining, present was associated loss genes increased proliferation, Zeb1 PTEN loss. In multivariate analysis, only significantly shorter overall survival. These results suggest persistence signaling number cases, interest staining biomarker.