title: Complete absence of M2-pyruvate kinase expression in benign pancreatic ductal epithelium and pancreaticobiliary and duodenal neoplasia.
abstract: BACKGROUND
  Elevated serum concentrations of M2-pyruvate kinase (M2-PK) correlate with poor prognosis in patients with pancreaticobiliary and duodenal cancer, but the expression of M2-PK in formalin-fixed pancreatic tissue is unknown. We aimed to characterise the immunohistochemical expression of M2-PK in archived specimens of pancreaticobiliary and duodenal cancers, premalignant lesions, chronic pancreatitis, and normal pancreas.
  
  
  METHODS
  Immunohistochemical staining was performed with mouse anti-M2-PK monoclonal antibody (clone DF-4) at an optimal dilution of 1:25 on tissue microarrays constructed from formalin-fixed paraffin-embedded pancreatic tissue of 126 consecutive patients undergoing pancreatic resections between June 2001 and June 2006. 104 underwent resection for cancer and 22 for chronic pancreatitis. 78 specimens of chronic pancreatitis tissue were obtained adjacent to areas of cancer. Normal pancreatic tissue was obtained from the resection specimens in a total of 30 patients. Metastatic tumours in 61 regional lymph nodes from 61 patients were also studied. A further 11 premalignant pancreaticobiliary and duodenal lesions were studied. M2-PK expression was quantified with the immunohistochemical score (IHS; Range 0-12).
  
  
  RESULTS
  Benign non-ductal tissue in chronic pancreatitis and normal pancreas showed variable expression of M2-PK (IHS = 1 in 25%, IHS = 2-3 in 40%, IHS>3 in 40%). Benign pancreatic ductal epithelium, all primary pancreaticobiliary and duodenal premalignant lesions and cancers (and lymph node metastasis) showed complete lack of expression (IHS = 0).
  
  
  CONCLUSIONS
  Complete lack of M2-PK expression was observed in benign pancreatic ducts, premalignant lesions and cancer. M2-PK is present only in benign non-ductal epithelium in normal pancreas and peri-tumoural tissue.
authors.affiliation: Division of Gastrointestinal Surgery, Nottingham Digestive Diseases Centre NIHR Biomedical Research Unit, Nottingham University Hospitals, Queen's Medical Centre, Nottingham NG7 2UH, UK. mark.aloysius@nottingham.ac.uk
authors.forename: Mark M
authors.initials: MM
authors.lastname: Aloysius
authors.forename: Abed M
authors.initials: AM
authors.lastname: Zaitoun
authors.forename: Timothy E
authors.initials: TE
authors.lastname: Bates
authors.forename: Abdulkader
authors.initials: A
authors.lastname: Albasri
authors.forename: Mohammad
authors.initials: M
authors.lastname: Ilyas
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Rowlands
authors.forename: Dileep N
authors.initials: DN
authors.lastname: Lobo
mesh_terms: D000368:Aged; D021441:Carcinoma, Pancreatic Ductal / Q000201:enzymology* / Q000235:genetics / Q000473:pathology; D004379:Duodenal Neoplasms / Q000201:enzymology* / Q000235:genetics / Q000473:pathology; D004848:Epithelium / Q000201:enzymology / Q000473:pathology; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008297:Male; D008875:Middle Aged; D010179:Pancreas / Q000166:cytology / Q000201:enzymology / Q000473:pathology; D010190:Pancreatic Neoplasms / Q000201:enzymology* / Q000235:genetics / Q000473:pathology; D011770:Pyruvate Kinase / Q000235:genetics* / Q000378:metabolism
chemical_list: D011770:Pyruvate Kinase