Multiple genetic alterations and behavior of cellular biology in gastric cancer and other gastric mucosal lesions:H.pylori infection, histological types and staging

Abstract

AIM:To investigate the expression of multiple genes and the behavior of cellular biology in gastric cancer (GC) and other gastric mucosal lesions and their relations to Helicobacter pylori (H. pylori) infection, tumor staging and histological subtypes.METHODS:Three hundred and twenty seven specimens of gastric mucosa obtained via endoscopy or surgical resection, and ABC immunohistochemical staining were used to detect the expression of p53, p16, Bcl-2 and COX-2 proteins.H. pylori was determined by rapid urea test combined with patholo-gical staining or 14 Curea breath test. Cellular image analysis was performed in 66 patients with intestinal metaplasia (IM) and/or dysplasia (Dys). In 30 of them, both cancer and the paracancerous tissues were obtained at the time of surgery. Histolo-gical pattern, tumor staging, lymph node metastasis, grading of differentiation and other clinical data were studied in the medical records.RESULTS:p16 expression of IM or Dys was significantly lower in positive H. pylori chronic atrophic gastritis (CAG) than those with negative H. pylori (CAG: 54.8% vs 88.0%, IM:34.4% vs 69.6%, Dys: 23.8% vs 53.6%, all P < 0.05), Bcl-2 or COX-2 expression of IM or Dys in positive H. pylori cases was signi-ficantly higher than that without H. pylori (Bcl-2: 68.8% vs 23.9%, 90.5% vs 60.7%; COX-2: 50.0% vs 10.8%, 61.8% vs 17.8%; all P <0.05). The mean number of most parame-ters of cellular image analysis in positive H. pylori group was significantly higher than that in negative H. pylori group (Ellipser: 53 plus minus 14, 40 plus minus 12&mgr;m, Area(1): 748 plus minus 572, 302 plus minus 202&mgr;m(2), Area(2): 3050 plus minus 1661, 1681 plus minus 1990&mgr;m(2), all P< 0.05; Ellipseb: 79 plus minus 23, 58 plus minus 15&mgr;m, Ratio-1: 22% plus minus5%,13% plus minus4%,Ratio-2:79% plus minus17%,53% plus minus20%,all P<0.01). There was significant correl-ation between Bcl-2 and histologic pattern of gastric carcinoma, and between COX-2 and tumor staging or lymph node metasta sis (Bcl-2: 75.0% vs16.7%; COX-2: 76.0% vs 20.0%, 79.2% vs 16.7%; all P< 0.05).CONCLUSION:p16, Bcl-2, and COX-2 but not p53 gene may play a role in the early genesis/progression of gastric carcinoma and are associated with H. pylori infection. p53 gene is relatively late event in gastric tumorigenesis and mainly relates to its progression. There is more cellular-biological behavior of malignant tumor in gastric mucosal lesions with H. pylori infec-tion. Aberrant Bcl-2 protein expression appears to be preferentially associated with the intestinal type cancer. COX-2 seems to be related to tumor staging and lymph node metastasis.