title: Expression of protein C (PC), protein S (PS) and thrombomodulin (TM) in human colorectal cancer.
abstract: BACKGROUND
  Colorectal cancer (CRC) is often complicated by thromboembolic episodes. It has been recognized that blood coagulation proteins play a role in cancer progression. An important inhibitory mechanism is provided by the protein C (PC) system consisting of PC, protein S (PS) and thrombomodulin (TM). Recently, novel biological activities have been ascribed to the PC system that do not relate to their hemostatic functions, eg. in angiogenesis, apoptosis and inflammation.
  
  
  OBJECTIVE
  The purpose of the study was to elucidate the solid phase interactions between CRC tissue and components of the PC system that may contribute to tumor progression.
  
  
  METHODS
  CRC tissues were obtained at surgical resection during treatment of 66 patients. Immunohistochemical studies were performed using polyclonal antibodies against PC, PS and TM. A semiquantitative analysis of the protein expression was also performed.
  
  
  RESULTS
  Weak expression of PC was observed in cancer cells of two-thirds of the specimens examined, while in 3/66 cases there was no staining for PC in cancer cells. One fourth of CRCs exhibited strong expression of PC. The presence of PS was demonstrated in 64/66 cases of CRC. However, its expression was irregular in terms of intensity of staining and percentage of cancer cells exhibiting protein expression. Weak expression of TM was demonstrated in two thirds of the cases examined, while a strong TM staining was revealed in one third of colon cancers.
  
  
  CONCLUSIONS
  Heterogeneous expression of the PC system components in CRC tissue may point to their biological activity modulating tumor growth.
authors.affiliation: Department of Oncology, Medical University, Bialystok, Poland.
authors.forename: Ewa
authors.initials: E
authors.lastname: Sierko
authors.forename: Marek Z
authors.initials: MZ
authors.lastname: Wojtukiewicz
authors.forename: Roman
authors.initials: R
authors.lastname: Zawadzki
authors.forename: Lech
authors.initials: L
authors.lastname: Zimnoch
authors.forename: Walter
authors.initials: W
authors.lastname: Kisiel
mesh_terms: D000328:Adult; D000925:Anticoagulants / Q000378:metabolism*; D015179:Colorectal Neoplasms / Q000378:metabolism* / Q000473:pathology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D011486:Protein C / Q000378:metabolism*; D017293:Protein S / Q000378:metabolism*; D018180:Thrombomodulin / Q000378:metabolism*
chemical_list: D000925:Anticoagulants; D011486:Protein C; D017293:Protein S; D018180:Thrombomodulin