AIM To investigate the expression of multiplegenes and the behavior of cellular biology ingastric cancer(GC)and other gastric mucosallesions and their relations to Helicobacter pylori(H.pylori)infection,tumor staging andhistological subtypes.METHODS Three hundred and twenty-sevenspecimens of gastric mucosa obtained viaendoscopy or surgical resection,and ABCimmunohistochemical staining were used todetect the expression of p53,p16,Bcl-2 andCOX-2 proteins.H.pylori was determined byrapid urea test combined with pathologicalstaining or~(14)C urea breath test.Cellular image analysis was performed in 66 patients withintestinal metaplasia(IM)and/or dysplasia(Dys).In 30 of them,both cancer and theparacancerous tissues were obtained at the timeof surgery.Histological pattern,tumor staging,lymph node metastasis,grading ofdifferentiation and other clinical data werestudied in the medical records.RESULTS p16 expression of IM or Dys wassignificantly lower in positive H.pylori chronicatrophic gastritis(CAG)than those withnegative H.pylori(CAG:54.8% vs 88.0%,IM:34.4% vs 69.6%,Dys:23.8% vs 53.6%,allP<0.05),Bcl-2 or COX-2 expression of IM orDys in positive H.pylori cases was significantlyhigher than that without H.pylori(Bcl-2:68.8%vs23.9%,90.5% vs 60.7%;COX-2:50.0% vs10.8%,61.8% vs 17.8%;all P<0.05).Themean number of most parameters of cellularimage analysis in positive H.pylori group wassignificantly higher than that in negative H.pylori group(Ellipser:53±14,40±12μm,Area_1:748±572,302±202 μm~2,Area_2:3050±1661,1681±1990 μm~2,all P<0.05;Ellipseb:79±23,58±15 μm,Ratio_1:22%±5%,13%±4%,Ratio_2:79%±17%,53%±20%,all P<0.01).There was significant correlation between Bcl-2and histologic pattern of gastric carcinoma,andbetween COX-2 and tumor staging or lymph nodemetastasis(Bcl-2:75.0% vs 16.7%;COX-2:76.0% vs 20.0%,79.2% vs 16.7%;allP<0.05).CONCLUSION p1l6, 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 infection. 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. AIM To investigate the expression of multiple genes and the behavior of cellular biology ingastric cancer (GC) and other gastric mucosallesions and their relations to Helicobacter pylori (H. pylori) infection, tumor staging andhistological subtypes.METHODS Three hundred and twenty-sevenspecimens of gastric mucosa derived viaendoscopy 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 byrapid urea test combined with pathological staging or ~ (14) C urea breath test. Cellular image analysis was performed in 66 patients withintestinal metaplasia (IM) and / or dysplasia (Dys). In 30 of them, both cancer and the paracancerous tissues were obtained at the time of surgery. Histological pattern, tumor staging, lymph node metastasis, grading of differentiation and other clinical data werestudied in the medical records .RESULTS p16 expression of IM or Dys wassignificantly lower in positive H.pylori chronicatrophic gastrit (CAG: 54.8% vs 88.0%, IM: 34.4% vs 69.6%, Dys: 23.8% vs 53.6%, allP <0.05), Bcl-2 or COX-2 expression of IM orDys in positive H. pylori cases was significantlyhigher than that without H.pylori (Bcl-2: 68.8% vs 23.9%, 90.5% vs 60.7%; COX-2: 50.0% vs10.8%, 61.8% vs 17.8% all P <0.05) .Themean number of most parameters of cellularimage analysis in positive H.pylori group wassignificantly higher than that in negative in H.pylori group (Ellipser: 53 ± 14,40 ± 12 μm, Area_1: 748 ± 572,302 ± 202 μm ~ 2, Area_2: 3050 ± 1661, 1681 ± 1990 μm ~ 2, all P <0.05; Ellipseb: 79 ± 23,58 ± 15 μm, Ratio_1: 22% ± 5%, 13% ± 4%, Ratio_2: 79% ± All was significantly associated with Bcl-2 and histologic pattern of gastric carcinoma, and between COX-2 and tumor staging or lymph node metastasis (Bcl-2: 75.0% vs 16.7%; COX-2: 76.0% vs 20.0%, 79.2% vs 16.7%; allP <0.05) .CONCLUSION p1l6, Bcl-2, and COX-2 but not p53 gene may play a role in the early genesis / progression of gastric carcinoma and are associat ed with H. pyloThere is more cellular-biological behavior of malignant tumor in gastric mucosal lesions with H. pylori infection. 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.