title: Laminin 5 gamma 2 chain expression: a marker of early invasiveness in colorectal adenomas.
abstract: OBJECTIVE
  Polyps of the colon and rectum are considered to be premalignant lesions in the development of colorectal cancer. However, knowledge of how normal epithelial cells gain invasive properties is limited. Laminin 5 gamma 2 chain expression was investigated to determine the role of laminin 5 as a marker of potential invasiveness in colorectal polyps.
  
  
  METHODS
  Sixty seven polyps of different types (15 hyperplastic polyps, 12 serrated adenomas, 16 tubular adenomas, and 24 adenomas with a villous component) were assessed for gamma 2 chain expression of laminin 5 by immunohistochemistry on archival, paraffin wax embedded sections.
  
  
  RESULTS
  Ten polyps stained positive and the number of polyps expressing the laminin 5 gamma 2 chain increased significantly as the phenotype of the adenomas became more atypical: none of the 15 hyperplastic polyps, two of the 16 tubular adenomas (12.5%), and six of the 24 adenomas with a villous component (25%) were positive. Two of 12 (17%) serrated adenomas, regarded as a distinct form of colorectal neoplasia, showed gamma 2 chain expression. Furthermore, laminin 5 gamma 2 chain expression correlated with lesion size. Polyps smaller than 10 mm expressed the gamma 2 chain less frequently than did those equal to or larger than 10 mm.
  
  
  CONCLUSIONS
  Laminin 5 gamma 2 chain expression was found to increase progressively towards a more atypical phenotype of adenoma. The results suggest that, in the future, laminin 5 gamma 2 chain expression may be used as an indicator of incipient malignant transformation of a benign colorectal adenoma.
authors.affiliation: Centre of Gastrointestinal Disease, Department of Surgery, Ersta Hospital, S-11691, Stockholm, Sweden. claes.lenander@ersta.se
authors.forename: C
authors.initials: C
authors.lastname: Lenander
authors.forename: U J
authors.initials: UJ
authors.lastname: Roblick
authors.forename: J K
authors.initials: JK
authors.lastname: Habermann
authors.forename: A
authors.initials: A
authors.lastname: Ost
authors.forename: K
authors.initials: K
authors.lastname: Tryggvason
authors.forename: G
authors.initials: G
authors.lastname: Auer
mesh_terms: D000236:Adenoma / Q000737:chemistry* / Q000473:pathology; D014408:Biomarkers, Tumor / Q000032:analysis*; D016009:Chi-Square Distribution; D015179:Colorectal Neoplasms / Q000737:chemistry* / Q000473:pathology; D005260:Female; D006801:Humans; D007417:Intestinal Polyps / Q000473:pathology; D008297:Male; D009361:Neoplasm Invasiveness; D011230:Precancerous Conditions / Q000737:chemistry* / Q000473:pathology
chemical_list: D014408:Biomarkers, Tumor