title: Immunohistochemical markers of the hypoxic response can identify malignancy in phaeochromocytomas and paragangliomas and optimize the detection of tumours with VHL germline mutations.
abstract: BACKGROUND
  There are no reliable markers of malignancy in phaeochromocytomas (PCC) and paragangliomas (PGL). We investigated the relevance of the mammalian target of rapamycin (mTOR)/AKT and hypoxic pathways as novel immunohistochemical markers of malignancy.
  
  
  METHODS
  Tissue microarray blocks were constructed with a total of 100 tumours (10 metastatic) and 20 normal adrenomedullary samples. Sections were immunostained for hypoxia-inducible factor 1α (Hif-1α), vascular endothelial growth factor A (VEGF-A), mTOR, carbonic anhydrase IX (CaIX) and AKT. The predictive performance of these markers was studied using univariate, multivariate and receiver operating characteristic analyses.
  
  
  RESULTS
  In all, 100 consecutive patients, 64% PCC, 29% familial with a median tumour size of 4.7 cm (range 1-14) were included. Univariate analyses showed Hif-1α overexpression, tumour necrosis, size >5 cm, capsular and vascular invasion to be predictors of metastasis. In multivariate analysis, Hif-1α, necrosis and vascular invasion remained as independent predictors of metastasis. Hif-1α was the most discriminatory biomarker for the presence of metastatic diffusion. Strong membranous CaIX expression was seen in von Hippel-Lindau (VHL) PCC as opposed to other subtypes.
  
  
  CONCLUSIONS
  Lack of vascular invasion, tumour necrosis and low Hif-1α expression identify tumours with lower risk of malignancy. We propose membranous CaIX expression as a potential marker for VHL disease in patients presenting with PCC.
authors.affiliation: Department of Investigative Medicine, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK.
authors.forename: D J
authors.initials: DJ
authors.lastname: Pinato
authors.forename: R
authors.initials: R
authors.lastname: Ramachandran
authors.forename: S T K
authors.initials: ST
authors.lastname: Toussi
authors.forename: M
authors.initials: M
authors.lastname: Vergine
authors.forename: N
authors.initials: N
authors.lastname: Ngo
authors.forename: R
authors.initials: R
authors.lastname: Sharma
authors.forename: T
authors.initials: T
authors.lastname: Lloyd
authors.forename: K
authors.initials: K
authors.lastname: Meeran
authors.forename: F
authors.initials: F
authors.lastname: Palazzo
authors.forename: N
authors.initials: N
authors.lastname: Martin
authors.forename: B
authors.initials: B
authors.lastname: Khoo
authors.forename: R
authors.initials: R
authors.lastname: Dina
authors.forename: T M
authors.initials: TM
authors.lastname: Tan
mesh_terms: D000310:Adrenal Gland Neoplasms / Q000175:diagnosis / Q000235:genetics / Q000276:immunology; D000328:Adult; D000951:Antigens, Neoplasm / Q000032:analysis* / Q000276:immunology; D014408:Biomarkers, Tumor / Q000032:analysis / Q000235:genetics / Q000276:immunology; D000071231:Carbonic Anhydrase IX; D002256:Carbonic Anhydrases / Q000032:analysis* / Q000276:immunology; D015687:Cell Hypoxia; D005260:Female; D018095:Germ-Line Mutation; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000032:analysis* / Q000276:immunology; D007150:Immunohistochemistry; D008297:Male; D009362:Neoplasm Metastasis; D010235:Paraganglioma / Q000737:chemistry* / Q000175:diagnosis / Q000235:genetics*; D010673:Pheochromocytoma / Q000737:chemistry* / Q000175:diagnosis / Q000235:genetics*; D051057:Proto-Oncogene Proteins c-akt / Q000032:analysis / Q000276:immunology; D058570:TOR Serine-Threonine Kinases / Q000032:analysis / Q000276:immunology; D046888:Tissue Array Analysis; D042461:Vascular Endothelial Growth Factor A / Q000032:analysis / Q000276:immunology; D051794:Von Hippel-Lindau Tumor Suppressor Protein / Q000235:genetics*; D006623:von Hippel-Lindau Disease / Q000175:diagnosis / Q000235:genetics
chemical_list: D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D042461:Vascular Endothelial Growth Factor A; D051794:Von Hippel-Lindau Tumor Suppressor Protein; C546842:MTOR protein, human; D051057:Proto-Oncogene Proteins c-akt; D058570:TOR Serine-Threonine Kinases; C089226:CA9 protein, human; D000071231:Carbonic Anhydrase IX; D002256:Carbonic Anhydrases