Expression of Inducible Nitric Oxide Synthase, p53 and Bcl-2 in Gastric Precancerous and Cancerous Lesions： Correlation with Clinical Features

OBJECTIVE To explore the expression of inducible nitric oxide synthase (iNOS), p53 and bcl -2 in gastric precancerous and cancerous lesions and to examine the expression of these proteins in relation to clinical features. METHODS The expressions of iNOS, p53 and bcl-2 proteins in gastric precancerous and cancerous lesions and their correlations with the clinical features were determined using immunohistochemical assays (Power VisionTM two -step method) on 84 gastric carcinomas and 54 gastric atypical hyperplastic tissues. Apoptotic cells were evaluated by terminal deoxynucleotidyl transferase- mediated dUTP-biotin nick-end labeling (TUNEL). RESULTS Expression of iNOS, p53 and bcl-2 was significantly higher in gastric carcinoma (GC) tissues than in gastric atypical hyperplastic tissues. Among the 84 carcinomas, the expression of p53 was observed in 50 (59.52%), bcl-2 in 43 (51.19%), and iNOS in 65 (77.58%). Overex-pression of iNOS and bcl-2 in gastric carcinoma was related to tumor size and iNOS was related to the presence of lymph node metastasis (P< 0.05). The expression of proteins did not correlate with age, sex, stage of disease, or differentiation. Expression of iNOS in gastric carcinoma tissues was positively correlated with bcl-2 expression (X2=8.926, P=0.003), and also with p53 expression (X2= 5.2430, P= 0.022). The mean apoptotic indexes (Al) were 1.29%±0.50 in low-grade atypical hyperplasia (LG), 0.96%±0.36 in high-grade atypical hyperplasia (HG) and 0.70%±0.43 in GC, with the difference being significant between LG, HG and GC (P< 0.05). There was a significant positive correlation between iNOS expression and the Al in GC (t=3.0815, P=0.0028). CONCLUSION iNOS was expressed in the majority of gastric carcinoma tissues and correlated with cellular apoptosis associated with p53 and bcl -2 expression. iNOS overexpression is closely associated with p53 and bcl-2 accumulation status. iNOS may play a synergistic role in the pathogenesis of GC.

Expression of inducible nitric oxide synthase, p53 and bcl-2 in gastric precancerous and cancerous lesions: Correlation with clinical features

OBJECTIVE To explore the expression of inducible nitric oxide synthase (iNOS), p53 and bcl-2 in gastric precancerous and cancerous lesions and to examine the expression of these proteins in relation to clinical features. METHODS The expressions of iNOS, p53 and bcl-2 proteins in gastric precancerous and cancerous lesions and their correlations with the clinical features were determined using immunohistochemical assays (Power VisionTM two-step method) on 84 gastric carcinomas and 54 gastric atypical hyperplastic tissues. Apoptotic cells were evaluated by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling (TUNEL). RESULTS Expression of iNOS, p53 and bcl-2 was significantly higher in gastric carcinoma (GC) tissues than in gastric atypical hyperplastic tissues. Among the 84 carcinomas, the expression of p53 was observed in 50 (59.52%), bcl-2 in 43 (51.19%), and iNOS in 65 (77.58%). Overexpression of iNOS and bcl-2 in gastric carcinoma was related to tumor size and iNOS was related to the presence of lymph node metastasis (P<0.05). The expression of proteins did not correlate with age, sex, stage of disease, or differentiation. Expression of iNOS in gastric carcinoma tissues was positively correlated with bcl-2 expression (X ²=8.926, P=0.003), and also with p53 expression (X ²=5.2430, P=0.022). The mean apoptotic indexes (AI) were 1.29%±0.50 in low-grade atypical hyperplasia (LG), 0.96%±0.36 in high-grade atypical hyperplasia (HG) and 0.70%±0.43 in GC, with the difference being significant between LG, HG and GC (P<0.05). There was a significant positive correlation between iNOS expression and the AI in GC (t=3.0815, P=0.0028). CONCLUSION iNOS was expressed in the majority of gastric carcinoma tissues and correlated with cellular apoptosis associated with p53 and bcl-2 expression. iNOS overexpression is closely associated with p53 and bcl-2 accumulation status. iNOS may play a synergistic role in the pathogenesis of GC. This work was supported by the Project of Natural Science Foundation of the Education Department of Jiangsu Province of China (No. 05KJD320234 and 01KJB320011).