title: Practical and Robust Identification of Molecular Subtypes in Colorectal Cancer by Immunohistochemistry.
abstract: OBJECTIVE
  Recent transcriptomic analyses have identified four distinct molecular subtypes of colorectal cancer with evident clinical relevance. However, the requirement for sufficient quantities of bulk tumor and difficulties in obtaining high-quality genome-wide transcriptome data from formalin-fixed paraffin-embedded tissue are obstacles toward widespread adoption of this taxonomy. Here, we develop an immunohistochemistry-based classifier to validate the prognostic and predictive value of molecular colorectal cancer subtyping in a multicenter study.
  
  
  METHODS
  Tissue microarrays from 1,076 patients with colorectal cancer from four different cohorts were stained for five markers (CDX2, FRMD6, HTR2B, ZEB1, and KER) by immunohistochemistry and assessed for microsatellite instability. An automated classification system was trained on one cohort using quantitative image analysis or semiquantitative pathologist scoring of the cores as input and applied to three independent clinical cohorts.
  
  
  RESULTS
  This classifier demonstrated 87% concordance with the gold-standard transcriptome-based classification. Application to three validation datasets confirmed the poor prognosis of the mesenchymal-like molecular colorectal cancer subtype. In addition, retrospective analysis demonstrated the benefit of adding cetuximab to bevacizumab and chemotherapy in patients with RAS wild-type metastatic cancers of the canonical epithelial-like subtypes.
  
  
  CONCLUSIONS
  This study shows that a practical and robust immunohistochemical assay can be employed to identify molecular colorectal cancer subtypes and uncover subtype-specific therapeutic benefit. Finally, the described tool is available online for rapid classification of colorectal cancer samples, both in the format of an automated image analysis pipeline to score tumor core staining, and as a classifier based on semiquantitative pathology scoring. Clin Cancer Res; 23(2); 387-98. ©2016 AACR.
authors.affiliation: Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, United Kingdom.|Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts.
authors.forename: Anne
authors.initials: A
authors.lastname: Trinh
authors.affiliation: Cancer Center UMC Utrecht, University Medical Center Utrecht, Utrecht, the Netherlands.
authors.forename: Kari
authors.initials: K
authors.lastname: Trumpi
authors.affiliation: Laboratory for Experimental Oncology and Radiobiology (LEXOR), Center for Experimental Molecular Medicine (CEMM), Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands.|Department of Molecular Oncology, Genentech Inc., South San Francisco, California.
authors.forename: Felipe
authors.initials: F
authors.lastname: De Sousa E Melo
authors.affiliation: Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, United Kingdom.|Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong.
authors.forename: Xin
authors.initials: X
authors.lastname: Wang
authors.affiliation: Laboratory for Experimental Oncology and Radiobiology (LEXOR), Center for Experimental Molecular Medicine (CEMM), Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands.
authors.forename: Joan H
authors.initials: JH
authors.lastname: de Jong
authors.affiliation: Laboratory for Experimental Oncology and Radiobiology (LEXOR), Center for Experimental Molecular Medicine (CEMM), Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands.
authors.forename: Evelyn
authors.initials: E
authors.lastname: Fessler
authors.affiliation: Department of Surgery, Leiden University Medical Center, Leiden, the Netherlands.
authors.forename: Peter J K
authors.initials: PJ
authors.lastname: Kuppen
authors.affiliation: Department of Surgery, Leiden University Medical Center, Leiden, the Netherlands.
authors.forename: Marlies S
authors.initials: MS
authors.lastname: Reimers
authors.affiliation: Department of Surgery, Leiden University Medical Center, Leiden, the Netherlands.
authors.forename: Marloes
authors.initials: M
authors.lastname: Swets
authors.affiliation: Cancer Center UMC Utrecht, University Medical Center Utrecht, Utrecht, the Netherlands.
authors.forename: Miriam
authors.initials: M
authors.lastname: Koopman
authors.affiliation: Department of Pathology, Radboud University Medical Center, Nijmegen, the Netherlands.
authors.forename: Iris D
authors.initials: ID
authors.lastname: Nagtegaal
authors.affiliation: Department of Pathology, Lymphoma and Myeloma Center Amsterdam, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands.|Centre for Tumour Biology, Barts Cancer Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom.
authors.forename: Marnix
authors.initials: M
authors.lastname: Jansen
authors.affiliation: Department of Pathology, Lymphoma and Myeloma Center Amsterdam, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands.
authors.forename: Gerrit K J
authors.initials: GK
authors.lastname: Hooijer
authors.affiliation: Cancer Center UMC Utrecht, University Medical Center Utrecht, Utrecht, the Netherlands.
authors.forename: George J A
authors.initials: GJ
authors.lastname: Offerhaus
authors.affiliation: Cancer Center UMC Utrecht, University Medical Center Utrecht, Utrecht, the Netherlands.
authors.forename: Onno
authors.initials: O
authors.lastname: Kranenburg
authors.affiliation: Department of Medical Oncology, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands.
authors.forename: Cornelis J
authors.initials: CJ
authors.lastname: Punt
authors.affiliation: Laboratory for Experimental Oncology and Radiobiology (LEXOR), Center for Experimental Molecular Medicine (CEMM), Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands.
authors.forename: Jan Paul
authors.initials: JP
authors.lastname: Medema
authors.affiliation: Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, United Kingdom.
authors.forename: Florian
authors.initials: F
authors.lastname: Markowetz
authors.affiliation: Laboratory for Experimental Oncology and Radiobiology (LEXOR), Center for Experimental Molecular Medicine (CEMM), Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands. l.vermeulen@amc.uva.nl.
authors.forename: Louis
authors.initials: L
authors.lastname: Vermeulen
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000235:genetics*; D000071616:CDX2 Transcription Factor / Q000235:genetics; D000068818:Cetuximab / Q000008:administration & dosage; D002986:Clinical Trials as Topic; D015179:Colorectal Neoplasms / Q000145:classification / Q000188:drug therapy / Q000235:genetics* / Q000473:pathology; D003598:Cytoskeletal Proteins / Q000235:genetics; D005260:Female; D020869:Gene Expression Profiling / Q000379:methods; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008565:Membrane Proteins / Q000235:genetics; D053842:Microsatellite Instability; D008875:Middle Aged; D011379:Prognosis; D011509:Proteoglycans / Q000235:genetics; D000071799:Zinc Finger E-box-Binding Homeobox 1 / Q000235:genetics
chemical_list: D014408:Biomarkers, Tumor; D000071616:CDX2 Transcription Factor; C491270:CDX2 protein, human; D003598:Cytoskeletal Proteins; C504793:FRMD6 protein, human; C490948:KERA protein, human; D008565:Membrane Proteins; D011509:Proteoglycans; C486307:ZEB1 protein, human; D000071799:Zinc Finger E-box-Binding Homeobox 1; D000068818:Cetuximab