title: Differential expression of basement membrane type IV collagen alpha chains in gastric intramucosal neoplastic lesions.
abstract: BACKGROUND
  The histological diagnosis of gastric intramucosal neoplastic lesions (GINLs) is controversial among experienced pathologists. Although the destruction of the epithelial basement membrane (BM) and the invasion of neoplastic epithelial cells into the interstitium of the lamina propria is distinct proof of "intramucosal carcinoma," histological evaluation of GINLs is difficult and ambiguous, especially intestinal-type adenocarcinoma. Type IV collagen is a major component of the BM, and comprises six genetically distinct alpha(IV) chains, alpha1(IV) to alpha6(IV). In several types of carcinomas, the loss of alpha5/alpha6(IV) chains of the epithelial BM at an early invasive stage has been reported. However, the expression of alpha5/alpha6(IV) chains in GINLs is still unclear. We examined the immunohistochemical expression of alpha(IV) chains in GINLs and investigated whether the expression pattern was a diagnostic marker of gastric intramucosal carcinoma.
  
  
  METHODS
  The expression of alpha(IV) chains and Ki-67 in 60 resected GINL specimens was immunohistochemically examined.
  
  
  RESULTS
  In normal gastric epithelium, alpha1(IV), alpha2(IV), alpha5(IV), and alpha6(IV) chains were expressed continuously in the BM. In most tubular adenomas (Japanese classification), these four chains were stained continuously in the BM, whereas in tubular adenocarcinomas (Japanese classification), the alpha5/alpha6(IV) chains had disappeared, partially or completely. The expression of alpha5/alpha6(IV) chains was closely related to the grade of histological atypia. In addition, the loss of alpha5/alpha6(IV) chains was significantly correlated with tumor cell growth activity.
  
  
  CONCLUSIONS
  The loss of alpha5/alpha6(IV) chains might be a useful diagnostic finding for gastric intramucosal carcinoma in GINL cases.
authors.affiliation: Department of Gastroenterological Surgery, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Baba
authors.forename: Ken-Ichi
authors.initials: K
authors.lastname: Iyama
authors.forename: Koei
authors.initials: K
authors.lastname: Ikeda
authors.forename: Shinji
authors.initials: S
authors.lastname: Ishikawa
authors.forename: Naoko
authors.initials: N
authors.lastname: Hayashi
authors.forename: Nobutomo
authors.initials: N
authors.lastname: Miyanari
authors.forename: Yumi
authors.initials: Y
authors.lastname: Honda
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Sado
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Ninomiya
authors.forename: Hideo
authors.initials: H
authors.lastname: Baba
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis / Q000378:metabolism* / Q000473:pathology; D000236:Adenoma / Q000175:diagnosis / Q000378:metabolism / Q000473:pathology; D001485:Basement Membrane / Q000378:metabolism* / Q000473:pathology; D024141:Collagen Type IV / Q000145:classification / Q000378:metabolism*; D004848:Epithelium / Q000378:metabolism / Q000473:pathology; D005753:Gastric Mucosa / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000378:metabolism; D013274:Stomach Neoplasms / Q000175:diagnosis / Q000378:metabolism* / Q000473:pathology
chemical_list: D024141:Collagen Type IV; D019394:Ki-67 Antigen