title: CDH17 Is a More Sensitive Marker for Gastric Adenocarcinoma Than CK20 and CDX2.
abstract: BACKGROUND
  -CDH17, which is expressed in the intestinal epithelium, is a novel oncogene involved in tumor invasion and metastasis. A panel consisting of cytokeratin (CK) 7, CD20, and CDX2 antibodies is typically used to diagnose gastrointestinal adenocarcinomas. However, studies have shown that CDH17 is a highly specific marker for gastrointestinal adenocarcinoma and may be important in clinical diagnosis.
  
  
  OBJECTIVE
  -To evaluate the sensitivity and specificity of CDH17, CK20, and CDX2 antibodies in neoplastic tissues, with emphasis on colon, stomach, and esophageal gastrointestinal lineage.
  
  
  METHODS
  -Immunohistochemistry was performed with CDH17, CK20, and CDX2 antibodies on formalin-fixed, paraffin-embedded tissue microarrays from normal (n = 26) and neoplastic (n = 884) tissues.
  
  
  RESULTS
  -CDH17 immunostaining was positive in 97.3% (145 of 149) of colon adenocarcinomas, whereas CK20 and CDX2 stained positively in 88.6% (132 of 149) and 93.3% (139 of 149), respectively. In metastatic colon cancers, CDH17, CK20, and CDX2 positive staining was observed in 90.6% (29 of 32), 59.4% (19 of 32), and 81.3% (26 of 32) of cases, respectively. In stomach adenocarcinomas, CDH17 positively stained 64.0% (112 of 175) of tissues, compared to CK20 and CDX2, where staining was observed in only 24.6% (43 of 175) and 46.9% (82 of 175), respectively. In esophageal adenocarcinomas, CDH17, CK20, and CDX2 stained 38.7% (12 of 31), 25.8% (8 of 31), and 29% (9 of 31) of specimens, respectively. Low or no expression was observed in other neoplastic tissues, except pancreatic cancers, where CDH17 displayed higher expression than CK20 and CDX2.
  
  
  CONCLUSIONS
  -CDH17 is a specific and more sensitive marker in the gastrointestinal tract than CK20 and CDX2. CDH17 may be especially valuable when gastrointestinal tumors are suspected in cancers of unknown primary.
authors.forename: David
authors.initials: D
authors.lastname: Altree-Tacha
authors.forename: Jillian
authors.initials: J
authors.lastname: Tyrrell
authors.affiliation: From Chief Scientific Officer (Dr Altree-Tacha) and the Department of Research and Development (Dr Tyrrell), Biocare Medical, Concord, California; and the Department of Pathology, Mercy Health System, Janesville, Wisconsin (Dr Haas).
authors.forename: Thomas
authors.initials: T
authors.lastname: Haas
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis / Q000378:metabolism*; D014408:Biomarkers, Tumor / Q000032:analysis*; D000071616:CDX2 Transcription Factor / Q000032:analysis*; D015820:Cadherins / Q000032:analysis*; D005404:Fixatives; D005557:Formaldehyde; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods / Q000706:statistics & numerical data; D053554:Keratin-20 / Q000032:analysis; D016612:Paraffin Embedding; D012680:Sensitivity and Specificity; D013274:Stomach Neoplasms / Q000175:diagnosis / Q000378:metabolism*; D046888:Tissue Array Analysis / Q000379:methods / Q000706:statistics & numerical data; D016707:Tissue Fixation
chemical_list: D014408:Biomarkers, Tumor; C490584:CDH17 protein, human; D000071616:CDX2 Transcription Factor; C491270:CDX2 protein, human; D015820:Cadherins; D005404:Fixatives; C507499:KRT20 protein, human; D053554:Keratin-20; D005557:Formaldehyde