title: Expression of protein C inhibitor (PCI) in benign and malignant prostatic tissues.
abstract: BACKGROUND
  Protein C inhibitor (PCI) occurs at high concentration in seminal plasma, and inhibits human glandular kallikrein-2 and, less readily, prostate-specific antigen. Previous studies have localized PCI in the male genital tract. Here we have performed a detailed investigation of PCI expression in the prostatic tissues, metastases, and cell lines.
  
  
  METHODS
  Immunohistochemistry, in situ hybridization, and Western blotting were used to study prostatic tissues, metastases, and PC-3, DU-145, and LNCaP cells.
  
  
  RESULTS
  PCI was immunolocalized in tissue microarray spots with BPH epithelium (detection rate 100%), PIN lesions (100%), tumors (96%), metastases (88%), and in all cell lines. ISH and WB supported the findings.
  
  
  CONCLUSIONS
  PCI is widely expressed in benign prostatic epithelium, and may act as a local regulator of enzymatic activity in seminal fluid, of importance for normal sperm function. Lack of PCI expression in a subpopulation of high-grade tumor cells in combination with maintained protease expression may facilitate invasive growth patterns.
mesh_terms: D000728:Androgens / Q000502:physiology; D015153:Blotting, Western; D002277:Carcinoma / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008297:Male; D009376:Neoplasms, Hormone-Dependent / Q000235:genetics / Q000378:metabolism*; D017430:Prostate-Specific Antigen / Q000235:genetics / Q000378:metabolism; D011470:Prostatic Hyperplasia / Q000235:genetics / Q000378:metabolism*; D011471:Prostatic Neoplasms / Q000235:genetics / Q000378:metabolism*; D018046:Protein C Inhibitor / Q000096:biosynthesis* / Q000235:genetics; D012334:RNA, Neoplasm / Q000737:chemistry / Q000235:genetics
chemical_list: D000728:Androgens; D018046:Protein C Inhibitor; D012334:RNA, Neoplasm; D017430:Prostate-Specific Antigen