title: Integrative Analysis of DCE-MRI and Gene Expression Profiles in Construction of a Gene Classifier for Assessment of Hypoxia-Related Risk of Chemoradiotherapy Failure in Cervical Cancer.
abstract: OBJECTIVE
  A 31-gene expression signature reflected in dynamic contrast enhanced (DCE)-MR images and correlated with hypoxia-related aggressiveness in cervical cancer was identified in previous work. We here aimed to construct a dichotomous classifier with key signature genes and a predefined classification threshold that separated cervical cancer patients into a more and less hypoxic group with different outcome to chemoradiotherapy.
  
  
  METHODS
  A training cohort of 42 patients and two independent cohorts of 108 and 131 patients were included. Gene expression data were generated from tumor biopsies by two Illumina array generations (WG-6, HT-12). Technical transfer of the classifier to a reverse transcription quantitative PCR (RT-qPCR) platform was performed for 74 patients. The amplitude ABrix in the Brix pharmacokinetic model was extracted from DCE-MR images of 64 patients and used as an indicator of hypoxia.
  
  
  RESULTS
  Classifier candidates were constructed by integrative analysis of ABrix and gene expression profiles in the training cohort and evaluated by a leave-one-out cross-validation approach. On the basis of their ability to separate patients correctly according to hypoxia status, a 6-gene classifier was identified. The classifier separated the patients into two groups with different progression-free survival probability. The robustness of the classifier was demonstrated by successful validation of hypoxia association and prognostic value across cohorts, array generations, and assay platforms. The prognostic value was independent of existing clinical markers, regardless of clinical endpoints.
  
  
  CONCLUSIONS
  A robust DCE-MRI-associated gene classifier has been constructed that may be used to achieve an early indication of patients' risk of hypoxia-related chemoradiotherapy failure. Clin Cancer Res; 22(16); 4067-76. ©2016 AACR.
authors.affiliation: Department of Radiation Biology, Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway.
authors.forename: Christina S
authors.initials: CS
authors.lastname: Fjeldbo
authors.affiliation: Department of Radiation Biology, Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway.
authors.forename: Cathinka H
authors.initials: CH
authors.lastname: Julin
authors.affiliation: Department of Radiation Biology, Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway.
authors.forename: Malin
authors.initials: M
authors.lastname: Lando
authors.affiliation: Department of Radiation Biology, Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway.
authors.forename: Malin F
authors.initials: MF
authors.lastname: Forsberg
authors.affiliation: Department of Radiation Biology, Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway.
authors.forename: Eva-Katrine
authors.initials: EK
authors.lastname: Aarnes
authors.affiliation: Department of Experimental Clinical Oncology, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Jan
authors.initials: J
authors.lastname: Alsner
authors.affiliation: Department of Gynaecologic Oncology, Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway. Institute for Cancer Genetics and Informatics, Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway. Faculty of Medicine, University of Oslo, Oslo, Norway.
authors.forename: Gunnar B
authors.initials: GB
authors.lastname: Kristensen
authors.affiliation: Department of Medical Physics, Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway. Department of Physics, University of Oslo, Oslo, Norway.
authors.forename: Eirik
authors.initials: E
authors.lastname: Malinen
authors.affiliation: Department of Radiation Biology, Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway. heidi.lyng@rr-research.no.
authors.forename: Heidi
authors.initials: H
authors.lastname: Lyng
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D059248:Chemoradiotherapy; D015331:Cohort Studies; D003131:Combined Modality Therapy; D005260:Female; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D000860:Hypoxia / Q000235:genetics* / Q000378:metabolism; D007089:Image Enhancement; D008279:Magnetic Resonance Imaging / Q000379:methods; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009367:Neoplasm Staging; D011379:Prognosis; D016016:Proportional Hazards Models; D059467:Transcriptome; D017211:Treatment Failure; D016896:Treatment Outcome; D002583:Uterine Cervical Neoplasms / Q000175:diagnosis* / Q000235:genetics* / Q000401:mortality / Q000628:therapy; D055815:Young Adult