title: Serum prosaposin levels are increased in patients with advanced prostate cancer.
abstract: BACKGROUND
  We previously cloned prosaposin (PSAP) from metastatic castrate-resistant prostate cancer (mCRPCa) cells and demonstrated its genomic amplification and/or overexpression in metastatic PCa cell lines, xenografts, and lymph node metastases. The clinicohistopathological significance of serum PSAP levels and its tissue expression and association with predictive or prognostic variable in primary or advanced PCa are not known.
  
  
  METHODS
  We examined PSAP expression by immunohistochemical staining during early embryogenic development of the prostate and within a large tissue microarray which included 266 benign and malignant prostate tissues. In addition, serum PSAP levels in the age-adjusted normal male population and in 154 normal individuals and patients with primary or mCRPCa were measured by an ELISA assay.
  
  
  RESULTS
  Univariate and multivariate analyses revealed a significant and inverse association between PSAP expression and clinical stages II and III tumors, dominant Gleason patterns 3 and 4, and seminal vesicle invasion. In the normal male population, the lowest serum PSAP level was detected before puberty, peaked at the most reproductive age group (20- to 39-year old), and then, decreased to a range between the two groups for men above 40-year old. Regardless of age and when compared with normal individuals, serum PSAP levels significantly decreased in primary organ-confined PCa, but increased in those with mCRPCa.
  
  
  CONCLUSIONS
  Our results show that PSAP has the potential to differentiate between primary and advanced PCa. Additional large-scale studies are needed to define the usefulness of tissue expression or serum PSAP levels as a diagnostic or prognostic marker or as a therapeutic target in PCa.
authors.affiliation: Department of Urology, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA. Shahriar.Koochekpour@roswellpark.org
authors.forename: Shahriar
authors.initials: S
authors.lastname: Koochekpour
authors.forename: Siyi
authors.initials: S
authors.lastname: Hu
authors.forename: Cruz
authors.initials: C
authors.lastname: Vellasco-Gonzalez
authors.forename: Ruiz
authors.initials: R
authors.lastname: Bernardo
authors.forename: Gissu
authors.initials: G
authors.lastname: Azabdaftari
authors.forename: Guodong
authors.initials: G
authors.lastname: Zhu
authors.forename: Haiyen E
authors.initials: HE
authors.lastname: Zhau
authors.forename: Leland W K
authors.initials: LW
authors.lastname: Chung
authors.forename: Robert L
authors.initials: RL
authors.lastname: Vessella
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000375:Aging / Q000378:metabolism; D017209:Apoptosis; D014408:Biomarkers, Tumor / Q000097:blood; D016022:Case-Control Studies; D002369:Castration; D002648:Child; D002675:Child, Preschool; D018450:Disease Progression; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011467:Prostate / Q000196:embryology / Q000378:metabolism / Q000473:pathology; D011471:Prostatic Neoplasms / Q000097:blood* / Q000175:diagnosis* / Q000473:pathology; D049231:Saposins / Q000097:blood*; D012720:Severity of Illness Index; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor; C483345:PSAP protein, human; D049231:Saposins