title: Expression of cystatins, high molecular weight cytokeratin, and proliferation markers in prostatic adenocarcinoma and hyperplasia.
abstract: BACKGROUND
  Prostatic adenocarcinoma is the most common malignancy among men in the western world but the diagnostic and prognostic criteria for it are still not clearly defined. Additional means for its diagnosis and prognosis are clearly needed. Previously it has been shown that cystatin A is expressed in the basal cells of normal prostate and the expression disappears in prostatic carcinoma.
  
  
  METHODS
  We have now studied the expression of both cystatins A and B in benign prostatic hyperplasias (BPH), prostatic intraepithelial neoplasias (PIN) and carcinomas of the prostatic epithelium and compared it with the expression of high molecular weight (HMW) cytokeratin as well as the proliferation markers cyclin A and Ki-67. The expression of the proteins was immunohistochemically assessed using 33 total prostatectomy specimens.
  
  
  RESULTS
  Cystatin A was expressed in the basal cells in all cases of BPH, low-grade PIN, and high-grade PIN whereas carcinomas showed no staining of cystatin A. The 34 beta E12 cytokeratin expression was similar to basal cystatin A staining and was not seen in carcinoma foci. Cystatin B showed both nuclear and cytoplasmic expression in the columnar epithelial cells. The decrease in median cytoplasmic staining of cystatin B in carcinomas compared to other lesions was significant, but there was a significant increase in expression with dedifferentiation of carcinoma. Also cyclin A and Ki-67 staining were significantly different in non-carcinomatous foci compared to carcinoma foci and had a remarkably similar negative correlations with basal cystatin A and 34 beta E12 staining.
  
  
  CONCLUSIONS
  The results show that cystatin expression can be used as an aid in the diagnosis of prostatic adenocarcinoma and especially cystatin A in the distinction between high grade PIN and grade I carcinoma.
authors.affiliation: Department of Pathology, University of Turku and Turku Graduate School of Biomedical Sciences (TuBS), Finland.
authors.forename: Tuomas
authors.initials: T
authors.lastname: Mirtti
authors.forename: Kalle
authors.initials: K
authors.lastname: Alanen
authors.forename: Markku
authors.initials: M
authors.lastname: Kallajoki
authors.forename: Ari
authors.initials: A
authors.lastname: Rinne
authors.forename: Karl-Ove
authors.initials: KO
authors.lastname: Söderström
mesh_terms: D000230:Adenocarcinoma / Q000737:chemistry* / Q000473:pathology; D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis*; D002455:Cell Division; D019926:Cyclin B / Q000032:analysis; D055313:Cystatin B; D015891:Cystatins / Q000032:analysis*; D006801:Humans; D007633:Keratins / Q000032:analysis* / Q000737:chemistry; D019394:Ki-67 Antigen / Q000032:analysis; D008297:Male; D008875:Middle Aged; D008970:Molecular Weight; D009364:Neoplasm Recurrence, Local; D011237:Predictive Value of Tests; D011379:Prognosis; D011470:Prostatic Hyperplasia / Q000378:metabolism / Q000473:pathology; D011471:Prostatic Neoplasms / Q000737:chemistry* / Q000473:pathology
chemical_list: D014408:Biomarkers, Tumor; C524994:CSTB protein, human; D019926:Cyclin B; D015891:Cystatins; D019394:Ki-67 Antigen; D007633:Keratins; D055313:Cystatin B