title: A comparison of tumour M2-PK with carcinoembryonic antigen and CA19-9 in patients undergoing liver resection for colorectal metastases.
abstract: BACKGROUND
  The currently available tumour markers used in the management of patients with colorectal metastases are of limited value. Tumour M2-pyruvate kinase (TuM2-PK), a tumour-associated isoenzyme of pyruvate kinase, is elevated in patients with gastrointestinal cancer. This study has measured TuM2-PK levels in patients before and after resection of colorectal liver metastases (CLM).
  
  
  METHODS
  Fifty patients with CLM and no local residual disease had TuM2-PK levels measured before liver resection. In 20 patients, TuM2-PK levels were repeated at 2 weeks, 5 weeks and 5 months after resection. Plasma levels were analysed by enzyme-linked immunosorbent assay (ScheBo, Giessen, Germany). Carcinoembryonic antigen (CEA) and CA19-9 levels were measured at the same time periods by electrochemiluminescence immunoassay. CEA, CA19-9 and TuM2-PK levels were compared with the tumour number, volume, differentiation and stage. Cut-off values used for TuM2-PK, CEA and CA19-9 were 15 IU/ml, 10 ng/ml and 39 IU/ml, respectively.
  
  
  RESULTS
  TuM2-PK was elevated in 68%, CEA in 62% and CA19-9 in 40% of patients with CLM. TuM2-PK+CEA was elevated in 88% and TuM2-PK+CA19-9 in 78% of patients. A significant correlation was observed between tumour volume and CEA (r=0.34, P<0.05) and CA19-9 (r=0.49, P<0.005). TuM2-PK levels did not show a significant correlation with tumour differentiation, volume or the number of metastases. At 2 weeks after liver resection, CEA and CA19-9 levels had decreased to normal value in 73 and 67% of patients, respectively, but TuM2-PK remained elevated in all patients. At 5 weeks, TuM2-PK, CEA and CA19-9 levels decreased to normal in 64, 93 and 70% of patients, respectively, and at 5 months levels were normal in 58, 92 and 67%.
  
  
  CONCLUSIONS
  Plasma TuM2-PK is commonly elevated in patients with CLM. Levels do not correlate with tumour volume, number or differentiation. Levels remain elevated after liver resection, the cause of which requires further investigation.
authors.affiliation: University Department of Surgery, HPB and Liver Transplant Unit, Royal Free Hospital, Royal Free and University College Medical School, University College London, London, UK.
authors.forename: Yogesh
authors.initials: Y
authors.lastname: Kumar
authors.forename: Inigo R
authors.initials: IR
authors.lastname: Pinedo
authors.forename: Niteen
authors.initials: N
authors.lastname: Tapuria
authors.forename: Abigail
authors.initials: A
authors.lastname: Zabron
authors.forename: Brian R
authors.initials: BR
authors.lastname: Davidson
mesh_terms: D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000097:blood*; D018395:CA-19-9 Antigen / Q000097:blood*; D002272:Carcinoembryonic Antigen / Q000097:blood*; D016022:Case-Control Studies; D015179:Colorectal Neoplasms / Q000473:pathology / Q000601:surgery; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D006801:Humans; D007118:Immunoassay / Q000379:methods; D008113:Liver Neoplasms / Q000473:pathology / Q000556:secondary* / Q000601:surgery; D008163:Luminescent Measurements / Q000379:methods; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011184:Postoperative Period; D011770:Pyruvate Kinase / Q000097:blood*
chemical_list: D014408:Biomarkers, Tumor; D018395:CA-19-9 Antigen; D002272:Carcinoembryonic Antigen; D011770:Pyruvate Kinase