title: Thymidylate synthase expression in rectal cancer and proliferation, assessed by cyclin A and Ki-67 expression.
abstract: BACKGROUND
  Levels of the enzyme thymidylate synthase (TS) are of prognostic significance in colorectal cancer. It may be argued that the levels of TS merely reflect the proliferative activity and could be replaced by markers of proliferation.
  
  
  METHODS
  We used immunohistochemical approaches to examine the expression of TS, Cyclin A and Ki-67 in morphologically well-defined tumor areas in consecutive slices of rectal cancer, using the antibodies TS 106, NCL-Cyclin A and Mib-1.
  
  
  RESULTS
  There was a linear relationship between Cyclin A- and Ki-67-positive cells (p < 0.0001). There did not seem to be any significant relationship between TS-expression and the frequency of Cyclin A-positive cells (p = 0.1) but a significant correlation was observed between TS-expression and the frequency of Ki-67-positive cells (p = 0.02).
  
  
  CONCLUSIONS
  TS, immunohistochemically-detected in rectal cancer cells, is not associated with an accurate assessment of the proliferative stage. The prognostic value of TS determination can only partly be explained by the proliferative activity.
authors.affiliation: Department of Surgery, Karolinska Hospital, S-171 76 Stockholm, Sweden. david.edler@swipnet.se
authors.forename: David
authors.initials: D
authors.lastname: Edler
authors.forename: Marja
authors.initials: M
authors.lastname: Hallström
authors.forename: Peter
authors.initials: P
authors.lastname: Ragnhammar
authors.forename: Henric
authors.initials: H
authors.lastname: Blomgren
mesh_terms: D002455:Cell Division / Q000502:physiology; D016213:Cyclins / Q000096:biosynthesis*; D005557:Formaldehyde; D006801:Humans; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000096:biosynthesis*; D016612:Paraffin Embedding; D012004:Rectal Neoplasms / Q000201:enzymology* / Q000378:metabolism / Q000473:pathology; D013940:Thymidylate Synthase / Q000096:biosynthesis*; D016707:Tissue Fixation
chemical_list: D016213:Cyclins; D019394:Ki-67 Antigen; D005557:Formaldehyde; D013940:Thymidylate Synthase