title: Carbonic anhydrase 9 expression increases with vascular endothelial growth factor-targeted therapy and is predictive of outcome in metastatic clear cell renal cancer.
abstract: BACKGROUND
  There is a lack of biomarkers to predict outcome with targeted therapy in metastatic clear cell renal cancer (mccRCC). This may be because dynamic molecular changes occur with therapy.
  
  
  OBJECTIVE
  To explore if dynamic, targeted-therapy-driven molecular changes correlate with mccRCC outcome.
  
  
  METHODS
  Multiple frozen samples from primary tumours were taken from sunitinib-naïve (n=22) and sunitinib-treated mccRCC patients (n=23) for protein analysis. A cohort (n=86) of paired, untreated and sunitinib/pazopanib-treated mccRCC samples was used for validation. Array comparative genomic hybridisation (CGH) analysis and RNA interference (RNAi) was used to support the findings.
  
  
  METHODS
  Three cycles of sunitinib 50mg (4 wk on, 2 wk off).
  
  
  METHODS
  Reverse phase protein arrays (training set) and immunofluorescence automated quantitative analysis (validation set) assessed protein expression.
  
  
  CONCLUSIONS
  Differential expression between sunitinib-naïve and treated samples was seen in 30 of 55 proteins (p<0.05 for each). The proteins B-cell CLL/lymphoma 2 (BCL2), mutL homolog 1 (MLH1), carbonic anhydrase 9 (CA9), and mechanistic target of rapamycin (mTOR) (serine/threonine kinase) had both increased intratumoural variance and significant differential expression with therapy. The validation cohort confirmed increased CA9 expression with therapy. Multivariate analysis showed high CA9 expression after treatment was associated with longer survival (hazard ratio: 0.48; 95% confidence interval, 0.26-0.87; p=0.02). Array CGH profiles revealed sunitinib was associated with significant CA9 region loss. RNAi CA9 silencing in two cell lines inhibited the antiproliferative effects of sunitinib. Shortcomings of the study include selection of a specific protein for analysis, and the specific time points at which the treated tissue was analysed.
  
  
  CONCLUSIONS
  CA9 levels increase with targeted therapy in mccRCC. Lower CA9 levels are associated with a poor prognosis and possible resistance, as indicated by the validation cohort.
  
  
  RESULTS
  Drug treatment of advanced kidney cancer alters molecular markers of treatment resistance. Measuring carbonic anhydrase 9 levels may be helpful in determining which patients benefit from therapy.
authors.affiliation: Edinburgh Urological Cancer Group, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, UK; Scottish Collaboration On Translational Research into Renal Cell Cancer, UK.
authors.forename: Grant D
authors.initials: GD
authors.lastname: Stewart
authors.affiliation: Edinburgh Urological Cancer Group, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, UK; Scottish Collaboration On Translational Research into Renal Cell Cancer, UK.
authors.forename: Fiach C
authors.initials: FC
authors.lastname: O'Mahony
authors.affiliation: Edinburgh Urological Cancer Group, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, UK; Scottish Collaboration On Translational Research into Renal Cell Cancer, UK; MRC Human Genetics Unit, MRC IGMM, University of Edinburgh, Edinburgh, UK.
authors.forename: Alexander
authors.initials: A
authors.lastname: Laird
authors.affiliation: Department of Molecular Oncology, Barts Cancer Institute, Queen Mary University of London, London, UK.
authors.forename: Sukaina
authors.initials: S
authors.lastname: Rashid
authors.affiliation: Department of Molecular Oncology, Barts Cancer Institute, Queen Mary University of London, London, UK.
authors.forename: Sarah A
authors.initials: SA
authors.lastname: Martin
authors.affiliation: MRC Human Genetics Unit, MRC IGMM, University of Edinburgh, Edinburgh, UK.
authors.forename: Lel
authors.initials: L
authors.lastname: Eory
authors.affiliation: MRC Human Genetics Unit, MRC IGMM, University of Edinburgh, Edinburgh, UK.
authors.forename: Alexander L R
authors.initials: AL
authors.lastname: Lubbock
authors.affiliation: Edinburgh Urological Cancer Group, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, UK; Scottish Collaboration On Translational Research into Renal Cell Cancer, UK.
authors.forename: Jyoti
authors.initials: J
authors.lastname: Nanda
authors.affiliation: Edinburgh Urological Cancer Group, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, UK; Scottish Collaboration On Translational Research into Renal Cell Cancer, UK.
authors.forename: Marie
authors.initials: M
authors.lastname: O'Donnell
authors.affiliation: The Institute of Cancer Research, London, UK.
authors.forename: Alan
authors.initials: A
authors.lastname: Mackay
authors.affiliation: School of Medicine, University of St Andrews, St Andrews, Fife, UK.
authors.forename: Peter
authors.initials: P
authors.lastname: Mullen
authors.affiliation: Edinburgh Urological Cancer Group, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, UK; Scottish Collaboration On Translational Research into Renal Cell Cancer, UK.
authors.forename: S Alan
authors.initials: SA
authors.lastname: McNeill
authors.affiliation: Edinburgh Urological Cancer Group, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, UK; Scottish Collaboration On Translational Research into Renal Cell Cancer, UK.
authors.forename: Antony C P
authors.initials: AC
authors.lastname: Riddick
authors.affiliation: Scottish Collaboration On Translational Research into Renal Cell Cancer, UK; Royal Free Hospital, London, UK.
authors.forename: Michael
authors.initials: M
authors.lastname: Aitchison
authors.affiliation: Department of Molecular Oncology, Barts Cancer Institute, Queen Mary University of London, London, UK.
authors.forename: Daniel
authors.initials: D
authors.lastname: Berney
authors.affiliation: Netherlands Cancer Institute, Amsterdam, The Netherlands.
authors.forename: Axel
authors.initials: A
authors.lastname: Bex
authors.affiliation: MRC Human Genetics Unit, MRC IGMM, University of Edinburgh, Edinburgh, UK.
authors.forename: Ian M
authors.initials: IM
authors.lastname: Overton
authors.affiliation: Edinburgh Urological Cancer Group, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, UK; Scottish Collaboration On Translational Research into Renal Cell Cancer, UK; School of Medicine, University of St Andrews, St Andrews, Fife, UK.
authors.forename: David J
authors.initials: DJ
authors.lastname: Harrison
authors.affiliation: Barts Cancer Institute, Experimental Cancer Medicine Centre, Queen Mary University of London, London, UK. Electronic address: thomas.powles@bartshealth.nhs.uk.
authors.forename: Thomas
authors.initials: T
authors.lastname: Powles
mesh_terms: D000368:Aged; D000951:Antigens, Neoplasm / Q000235:genetics / Q000378:metabolism*; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism*; D000071231:Carbonic Anhydrase IX; D002256:Carbonic Anhydrases / Q000235:genetics / Q000378:metabolism*; D002292:Carcinoma, Renal Cell / Q000188:drug therapy* / Q000201:enzymology / Q000235:genetics / Q000556:secondary; D045744:Cell Line, Tumor; D055028:Comparative Genomic Hybridization; D006801:Humans; D007211:Indoles / Q000627:therapeutic use*; D007680:Kidney Neoplasms / Q000188:drug therapy* / Q000201:enzymology / Q000235:genetics / Q000473:pathology; D008297:Male; D008875:Middle Aged; D058990:Molecular Targeted Therapy; D010865:Pilot Projects; D011237:Predictive Value of Tests; D047428:Protein Kinase Inhibitors / Q000627:therapeutic use*; D040901:Proteomics / Q000379:methods; D011758:Pyrroles / Q000627:therapeutic use*; D034622:RNA Interference; D015203:Reproducibility of Results; D000077210:Sunitinib; D013997:Time Factors; D046888:Tissue Array Analysis; D014162:Transfection; D016896:Treatment Outcome; D015854:Up-Regulation; D042461:Vascular Endothelial Growth Factor A / Q000037:antagonists & inhibitors* / Q000378:metabolism
chemical_list: D000951:Antigens, Neoplasm; D000970:Antineoplastic Agents; D014408:Biomarkers, Tumor; D007211:Indoles; D047428:Protein Kinase Inhibitors; D011758:Pyrroles; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; C089226:CA9 protein, human; D000071231:Carbonic Anhydrase IX; D002256:Carbonic Anhydrases; D000077210:Sunitinib
keywords: Biomarker; CA9; Renal cancer; VEGF TKI