title: Neuroendocrine differentiation in castration-resistant prostate cancer: a systematic diagnostic attempt.
abstract: BACKGROUND
  Assessing the neuroendocrine (NE) pattern in castration-resistant prostate cancer (CRPC) may prove useful in selecting potential responders to target therapies such as somatostatin analogues. The aim of this study was to define a panel of markers or examinations appropriate to characterize NE differentiation (NED).
  
  
  METHODS
  Forty-seven patients with CRPC underwent a systematic diagnostic attempt to characterize the NE phenotype using a plasma blood test for chromogranin A (CgA) and immunohistochemical staining of needle biopsy-obtained specimens (CgA, somatostatin receptor 2 [SSTR2], Ki-67, and androgen receptors). In a subgroup of 26 patients, somatostatin receptor scintigraphy using (111)In-DTPA-d-Phe octreotide (octreotide scintigraphy; Octreoscan, Covidien, Hazelwood, MO) was also performed.
  
  
  RESULTS
  NED was found in 85.1% of patients (if serum CgA, tissular CgA, and tissular SSTR2 were considered separately: 54%, 67%, and 58%, respectively). Only 15% of the 26-patient subgroup had an abnormal octreotide scintigraphy result. Although p-CgA and t-CgA were associated with more aggressive disease with a worse prognosis, patients with positive tissular SSTR2 staining had longer overall survival (OS).
  
  
  CONCLUSIONS
  This systematic approach to explore the NED in a quite homogeneous group of patients with CRPC seems reproducible and appropriate. Further investigations are required to validate this panel and better characterize potential responders to targeted therapy.
authors.affiliation: Division of Urology, European Institute of Oncology, Milan, Italy. d.v.matei@gmail.com
authors.forename: Deliu-Victor
authors.initials: DV
authors.lastname: Matei
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Renne
authors.forename: Marcelo
authors.initials: M
authors.lastname: Pimentel
authors.forename: Maria Teresa
authors.initials: MT
authors.lastname: Sandri
authors.forename: Laura
authors.initials: L
authors.lastname: Zorzino
authors.forename: Edoardo
authors.initials: E
authors.lastname: Botteri
authors.forename: Concetta
authors.initials: C
authors.lastname: De Cicco
authors.forename: Gennaro
authors.initials: G
authors.lastname: Musi
authors.forename: Antonio
authors.initials: A
authors.lastname: Brescia
authors.forename: Federica
authors.initials: F
authors.lastname: Mazzoleni
authors.forename: Valeria
authors.initials: V
authors.lastname: Tringali
authors.forename: Serena
authors.initials: S
authors.lastname: Detti
authors.forename: Ottavio
authors.initials: O
authors.lastname: de Cobelli
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000097:blood* / Q000378:metabolism; D016022:Case-Control Studies; D053379:Chromogranin A / Q000097:blood* / Q000378:metabolism; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009376:Neoplasms, Hormone-Dependent / Q000097:blood / Q000401:mortality / Q000473:pathology*; D018358:Neuroendocrine Tumors / Q000097:blood / Q000401:mortality / Q000473:pathology*; D009919:Orchiectomy; D011467:Prostate / Q000378:metabolism / Q000473:pathology; D011471:Prostatic Neoplasms / Q000097:blood / Q000401:mortality / Q000473:pathology*; D011944:Receptors, Androgen / Q000378:metabolism; D017481:Receptors, Somatostatin / Q000378:metabolism
chemical_list: D014408:Biomarkers, Tumor; D053379:Chromogranin A; D011944:Receptors, Androgen; D017481:Receptors, Somatostatin; C574734:SSTR2 protein, human