title: Current status of tumor M2 pyruvate kinase (tumor M2-PK) as a biomarker of gastrointestinal malignancy.
abstract: BACKGROUND
  Tumor pyruvate kinase M2 (tumor M2-PK) is a key enzyme in the altered metabolism of tumor tissue. In cancer, it is known to be present in high concentrations in malignant tissue, plasma and other body fluids. A commercial enzyme-linked immunosorbent assay (ELISA) method exists for the detection of tumor M2-PK. This study undertakes a systematic review of the current literature on tumor M2-PK as a diagnostic tool and provides an overview of the current usage and scope of this emerging biomarker.
  
  
  METHODS
  The MEDINE and EMBASE databases were searched for English-language articles containing original data. MeSH headings used were pyruvate kinase, tumor and cancer. All case reports and review articles were excluded and a final study population of 30 manuscripts containing original data was obtained.
  
  
  RESULTS
  Eight articles evaluated plasma tumor M2-PK in 511 esophago-gastric cancer, 226 pancreatobiliary cancer and 470 colorectal cancer patients. Although there are inter-study variations in cut-off points, consistent findings include elevated levels in patients with malignancy with the degree of elevation corresponding to extent of disease.
  
  
  CONCLUSIONS
  Tumor M2-PK is elevated in a range of gastrointestinal malignancy. In pancreatobiliary malignancy, the weight of evidence suggests that the test can be used as an adjunctive diagnostic test in conjunction with CA 19-9 and also that it may be a valuable biomarker of adverse prognosis. Stool tumor M2-PK appears to be a promising test for colon cancer.
authors.affiliation: Hepatobiliary Surgery Unit, Manchester Royal Infirmary, Oxford Road, Manchester, M13 9 WL, UK.
authors.forename: Harsha R
authors.initials: HR
authors.lastname: Hathurusinghe
authors.forename: Kolitha S
authors.initials: KS
authors.lastname: Goonetilleke
authors.forename: Ajith K
authors.initials: AK
authors.lastname: Siriwardena
mesh_terms: D014408:Biomarkers, Tumor / Q000097:blood*; D004797:Enzyme-Linked Immunosorbent Assay; D005243:Feces / Q000737:chemistry; D005770:Gastrointestinal Neoplasms / Q000175:diagnosis* / Q000201:enzymology / Q000473:pathology; D009367:Neoplasm Staging; D010190:Pancreatic Neoplasms / Q000175:diagnosis / Q000201:enzymology / Q000473:pathology; D011237:Predictive Value of Tests; D011379:Prognosis; D011770:Pyruvate Kinase / Q000097:blood*; D012016:Reference Values
chemical_list: D014408:Biomarkers, Tumor; D011770:Pyruvate Kinase