title: Lactate dehydrogenase 5 expression in operable colorectal cancer: strong association with survival and activated vascular endothelial growth factor pathway--a report of the Tumour Angiogenesis Research Group.
abstract: OBJECTIVE
  Lactate dehydrogenase 5 (LDH-5) regulates, under hypoxic conditions, the anaerobic transformation of pyruvate to lactate for energy acquisition. Several studies have shown that serum LDH may be an ominous prognostic marker in malignant tumors. The clinical significance of tissue LDH-5, however, remains largely unexplored.
  
  
  METHODS
  We investigated the immunohistochemical expression of LDH-5 in a series of 128 stage II/III colorectal adenocarcinomas treated with surgery alone. In addition, markers of tumor hypoxia (hypoxia-inducible factor 1 alpha [HIF1alpha]), angiogenesis (vascular endothelial growth factor [VEGF] and phosporylated kinase domain receptor [pKDR]/flk-1 receptor) and the tumor vascular density (CD31 positive standard vascular density [sVD] and pKDR positive activated vascular density [aVD]) were assessed.
  
  
  RESULTS
  The expression of LDH-5, together with that of HIF1alpha and pKDR, was both nuclear and cytoplasmic. Assessment, with minimal interobserver variability, was achieved using a previously described scoring system. LDH-5 was significantly associated with HIF1alpha (P = .01), aVD (P = .001) and, particularly, with pKDR expression in cancer cells (P = .0001). Tissue LDH-5 expression was linked with elevated serum LDH levels, but serum levels failed to reflect tissue expression in 71% of LDH-5 positive cases. In univariate analysis tissue LDH-5 was associated with poor survival (P = .0003, HR 15.1), whereas in multivariate analysis this isoenzyme was the strongest independent prognostic factor (P = .0009). VEGF, pKDR, aVD, sVD and vascular invasion were all significantly related to unfavorable prognosis.
  
  
  CONCLUSIONS
  The immunohistochemical assessment of tissue LDH-5 and pKDR provides important prognostic information in operable colorectal cancer. The strong association between LDH-5 and pKDR expression would justify their use as surrogate markers to screen patients for tyrosine kinase inhibitor therapy.
authors.affiliation: Department of Pathology, Democritus University of Thrace, Alexandroupolis, Greece. targ@her.forthnet.gr
authors.forename: Michael I
authors.initials: MI
authors.lastname: Koukourakis
authors.forename: Alexandra
authors.initials: A
authors.lastname: Giatromanolaki
authors.forename: Efthimios
authors.initials: E
authors.lastname: Sivridis
authors.forename: Kevin C
authors.initials: KC
authors.lastname: Gatter
authors.forename: Adrian L
authors.initials: AL
authors.lastname: Harris
mesh_terms: D000230:Adenocarcinoma / Q000188:drug therapy / Q000201:enzymology* / Q000378:metabolism / Q000473:pathology; D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D014408:Biomarkers, Tumor / Q000378:metabolism*; D015179:Colorectal Neoplasms / Q000188:drug therapy / Q000201:enzymology* / Q000378:metabolism / Q000473:pathology; D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism*; D007150:Immunohistochemistry; D007527:Isoenzymes / Q000378:metabolism; D007770:L-Lactate Dehydrogenase / Q000378:metabolism*; D000080864:Lactate Dehydrogenase 5; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D011379:Prognosis; D047428:Protein Kinase Inhibitors / Q000627:therapeutic use; D016019:Survival Analysis; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000378:metabolism
chemical_list: D014408:Biomarkers, Tumor; C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D007527:Isoenzymes; D047428:Protein Kinase Inhibitors; D042461:Vascular Endothelial Growth Factor A; D007770:L-Lactate Dehydrogenase; D000080864:Lactate Dehydrogenase 5; D040301:Vascular Endothelial Growth Factor Receptor-2