title: A morphological and immunohistochemical evaluation of gastric carcinoma in the Western Cape province of South Africa.
abstract: BACKGROUND
  Gastric resections for carcinoma are common, but gastric carcinoma in South Africa, and particularly within the Western Cape province, has not been well documented.
  
  
  METHODS
  The objective of the study was to immunohistochemically evaluate HER2/ neu overexpression, determine aberrations in β-catenin and epithelial-cadherin (E-cadherin) expression, and correlate these fi ndings with gastric carcinoma subtypes.
  
  
  RESULTS
  Ninety-seven gastric adenocarcinoma resections were morphologically categorised as intestinal-, diffuse- or mixed-type adenocarcinomas, and immunohistochemically stained for β-catenin, E-cadherin (extracellular and cytoplasmic domains) and HER2/neu. The results of staining were compared between the subtypes for statistically signifi cant differences. All 97 cases were confi rmed as gastric adenocarcinomas, with 39 (40%) intestinal- type, 51 (53%) diffuse-type, and 7 (7%) mixed-type tumours identifi ed. Patient ages ranged from 18-84 years. HER2/neu was overexpressed in 12 (12%) cases, with intestinal-type morphology (p = 0.017) reported in nine. Fourteen cases (14%) demonstrated abnormal β-catenin localisation. Aberrant E-cadherin (extracellular domain) localisation occurred in 36 (37%) cases. Diffuse-type morphology was associated with a signifi cantly high proportion (p = ≤ 0.001). Aberrant E-cadherin (cytoplasmic domain) localisation occurred in 7 (7%) cases. A signifi cantly high proportion (six of these cases) (p = 0.023) of these was diffuse-type morphology. Eleven (11%) adenocarcinomas occurred in patients aged ≤ 40 years, with intestinal morphology reported in nine of these 11. Aberrant E-cadherin (extracellular domain) localisation was noted in seven of the 11, a signifi cantly high proportion when compared to that in the older patients (p = 0.025).
  
  
  CONCLUSIONS
  Distinct immunomorphological correlations are apparent in tumours demonstrating HER2/neu overexpression or abnormal E-cadherin localisation. Intestinal morphology, poor differentiation and E-cadherin abnormalities are frequently demonstrated in tumours occurring in younger individuals.
authors.affiliation: Division of Anatomical Pathology, National Health Laboratory Service and Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.
authors.forename: R
authors.initials: R
authors.lastname: Roberts
authors.affiliation: Division of Anatomical Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.
authors.forename: P
authors.initials: P
authors.lastname: Govender
authors.affiliation: Division of Anatomical Pathology, National Health Laboratory Service and Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.
authors.forename: R
authors.initials: R
authors.lastname: Naidoo
authors.affiliation: Division of Anatomical Pathology, National Health Laboratory Service and Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.
authors.forename: M
authors.initials: M
authors.lastname: Locketz