title: Pyruvate kinase M2 is a novel diagnostic marker and predicts tumor progression in human biliary tract cancer.
abstract: BACKGROUND
  The early diagnosis of biliary tract cancer (BTC) remains challenging, and there are few effective therapies. This study investigated whether the M2 isotype of pyruvate kinase (M2-PK), which serves as the key regulator of cellular energy metabolism in proliferating cells, could play a role in the diagnosis and therapy of BTC.
  
  
  METHODS
  Plasma and bile M2-PK concentrations were measured by enzyme-linked immunosorbent assay in 88 patients with BTC, 79 with benign biliary diseases, and 17 healthy controls. M2-PK expression was assayed in a BTC tissue array by immunohistochemistry. The role of M2-PK in tumor growth, invasion, and angiogenesis was evaluated in BTC cell lines by retrovirus-mediated M2-PK transfection and short hairpin RNA silencing techniques.
  
  
  RESULTS
  Sensitivity (90.3%) and specificity (84.3%) of bile M2-PK for malignancy were significantly higher than those for plasma M2-PK and serum carbohydrate antigen 19-9. M2-PK expression was specific for cancer cells and correlated with microvessel density. M2-PK positivity was a significant independent prognostic factor by multivariable analysis. Transfection of M2-PK in a negatively expressed cell line (HuCCT-1 cells) increased cell invasion, whereas silencing in an M2-PK-positive cell line (TFK cells) decreased tumor nodule formation and cellular invasion. A significant increase in endothelial tube formation was noted when supernatants from M2-PK-transfected cells were added to an in vitro angiogenesis assay, whereas supernatants from silenced cells negated endothelial tube formation.
  
  
  CONCLUSIONS
  Bile M2-PK is a novel tumor marker for BTC and correlates with tumor aggressiveness and poor outcome. Short hairpin RNA-mediated inhibition of M2-PK indicates the potential of M2-PK as a therapeutic target.
authors.affiliation: UCL Institute of Liver and Digestive Health, University College London Medical School, Royal Free Campus, London, United Kingdom.
authors.forename: Dipok Kumar
authors.initials: DK
authors.lastname: Dhar
authors.forename: Steven W M
authors.initials: SW
authors.lastname: Olde Damink
authors.forename: James Hal
authors.initials: JH
authors.lastname: Brindley
authors.forename: Andrew
authors.initials: A
authors.lastname: Godfrey
authors.forename: Michael H
authors.initials: MH
authors.lastname: Chapman
authors.forename: Neomal S
authors.initials: NS
authors.lastname: Sandanayake
authors.forename: Fausto
authors.initials: F
authors.lastname: Andreola
authors.forename: Sybille
authors.initials: S
authors.lastname: Mazurek
authors.forename: Tayyaba
authors.initials: T
authors.lastname: Hasan
authors.forename: Massimo
authors.initials: M
authors.lastname: Malago
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Pereira
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001646:Bile / Q000737:chemistry / Q000378:metabolism; D001661:Biliary Tract Neoplasms / Q000175:diagnosis* / Q000235:genetics / Q000401:mortality / Q000473:pathology; D014408:Biomarkers, Tumor / Q000097:blood / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D002277:Carcinoma / Q000175:diagnosis* / Q000235:genetics / Q000401:mortality / Q000473:pathology; D016022:Case-Control Studies; D045744:Cell Line, Tumor; D018450:Disease Progression; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011770:Pyruvate Kinase / Q000097:blood / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D016019:Survival Analysis
chemical_list: D014408:Biomarkers, Tumor; D011770:Pyruvate Kinase