The Relationship Between Cox â…¡ Expression In Gastric Carcinoma And Clinical Pathological Features

Background and Objective: Cytochrome oxidase (cytochrome c oxidase, COX)which is located in the mitochondrial inner membrane, is a key enzyme namely acomplex membrane protein to control the mitochondrial respiratory, including morethan one subunit and the metal active center. Its subunit Ⅱ(COX Ⅱ) is consideredto be the entrance of electrons from cytochrome C into the enzyme, which plays animportant role in physiological processes. The change or injury of COX will directlyaffect the mitochondrial dysfunction. Previous studies have found that COX defectsor deficiencies could lead to the occurrence of many diseases. However, the role ofCOX in the gastric carcinogenesis is not clear. This study detected the expression ofCOX Ⅱ protein in gastric cancer tissues, analyzed the relationship among theexpression of COXⅡ, Hp infection and the clinicopathological parameters of gastriccarcionma.Methods:Two kinds of tissue microarray were used to detect the expression of COXⅡprotein in normal gastric mucosa, adjacent tissues of gastric cancer, gastric cancer andlymph node metasta tissues of gastric cancer. This study collected wax paraffinblocks with35cases of normal gastric mucosa,25cases of precancerous lesions and53cases of gastric cancer. The expression of COXⅡ was detected in normal gastricmucosa, precancerous lesions, gastric cancer and lymph node metasta tissues byimmunohistochemistry (SP method) and Hp presence was detected in normal gastricmucosa, precancerous lesions and gastric cancer tissues by methylene blue staining toanalyze the relationship between the expression of COXⅡ and Hp infection and theclinicopathological parameters of gastric carcionma.Results: The expression of COXⅡ was detected by gastric cancer tissue microarray:COXⅡ protein was mainly displayed in cytoplasm of gastric cancer cells and browngranules were showed in the cytoplasm of positive cells. The positive expression rates ofCOXⅡ protein in normal gastric mucosa, adjacent tissues of gastric cancer, gastriccarcinoma and lymph nodes metastatic tissues were100%(10/10),48.89%(22/45),45.45%(20/44),25.00%(10/40), respectively. Compared the expression rate ofCOXⅡin normal gastric mucosa tissues with adjacent tissues of gastric cancer andgastric cancer tissues, the difference was statistically significant (p<0.05); however,the difference was not statistically significant (p>0.05) in primary gastric cancertissues and gastric cancer with lymph node metastasis group.The positive expression rates of COXⅡ protein in normal gastric mucosa,precancerous lesions and gastric cancer tissues were94.29%(33/35),52.00%(13/25),44.44%(24/54) respectively..Compared normal gastric mucosa tissues withprecancerous lesion tissues and gastric cancer tissues, the difference was statisticallysignificant (p<0.05); The positive expression was localized in the cytoplasm.Theexpression rates of COX Ⅱ in well-differentiated, middle-differentiated andpoorly-differentiated gastric adenocarcinoma group were46.15%(6/13),33.33%(6/18),52.17%(12/23) respectively, the difference was not statistically significant(p>0.05); the COXⅡ protein expression have no relationship with age, gender,depth of invasion, TNM staging or lymph node metastasis (p>0.05).The Hp， which was stained dark blue purple, short rod-like and slightlycurved， was distributed clearly and mainly located in the gland groove parts andglands of the shallow surface of gastric tissues.The infection rates of Hp in normalgastric mucosa, precancerous lesions and gastric cancer tissues were31.43%(11/35),84.00%(21/25),66.67%(33/54) respectively, Compared normal gastric mucosagroup with adjacent tissues of gastric cancer group and gastric cancer group, thedifference was statistically significant (p<0.05); compared gastric cancer group withprecancerous lesions tissues of gastric cancer group, the difference was statisticallysignificant (p <0.05). The positive expression rates of COXⅡ protein in normal gastric mucosa,precancerous lesions and gastric cancer tissues of the Hp infection were90.91%(10/11),42.86%(9/21),30.30%(10/33) respectively, The positive expression rate ofHp-positive group of COX Ⅱ is lower than of Hp-negative group in normal gastricmucosa, the difference was not statistically significant (p>0.05); The positiveexpression rate of Hp-positive group of COX Ⅱis lower than of Hp-negative groupin precancerous lesions, the difference was statistically significant (p<0.05); Thepositive expression rate of Hp-positive group of COX Ⅱis lower than of Hp-negativegroup in gastric cancer, the difference was statistically significant (p <0.05).Conclusions:1. The expression of COX Ⅱ in the precancerous lesion tissues and gastriccarcinoma tissues was low expression. The expression of COXⅡ was notcorrelated with the generation of gastric carcinoma, degree of differentiation oftissues or lymph node metastasis.2. Hp infection was negative correlated with COXⅡ expression.