Study On The Correlation Between Spiral CT Features And Expression Of COX-2,nm23-H₁ In Gastric Carcinoma

Background & Objective: Gastric carcinoma is one of the malignant tumors, which is threatening people's life and health. Its invasion and metastasis are the leading cause of death. Investigating the relationshipbetween outwards appearance and molecular mechanism in the development and metastasis of gastric carcinoma, therefore, is significant to radiology, pathology and molecular biology. Spiral CT can provide sufficient and accurate reflection on the characteristics of gastric carcinoma. So it is considered to be a practical and credible method to diagnose gastric carcinoma.Recent research revealed that cyclooxygenase -2(COX-2) is an inducible and rate-limiting enzyme in the conversion ofarachidonic acid to PGE2 (prostaglandin) which contributes to maintain the pathologic and physiologic function of organism and has close relationship with gastrointestinal cancer.nm23 is the best candidate gene which can restrain metastasis of cancer, low expression of nm23-Hi mRNA or protein was related to metastasis of cancer. In general, imaging feature of gastric carcinoma is determined by the pathologic alteration, and the latter is determined by its biologic characteristic. To investigate the molecular pathologic basement of Spiral CT features of gastric carcinoma and the relationshipbetween expressins of COX-2 and nm23-Hj and Spiral CT features, improve the accurate diagnosis of gastric carcinoma in metastasis and infiltration, and provide more valuable information to clinical doctors, here we compare macroscopically Spiral CT signs with microscopically pathologic features and expressions of COX-2 and nm23-Hi in gastric carcinoma.Materials and methods: Sixty-seven patients were performed Spiral CT examination before operation. Non-enhancment was performed with 120Kv, 240mAs, 10mm collimation, pitch =1:1. About 100ml of Omnipaque (300mgI/ml), was administered with a power injector at a flow rate of 3ml/sec. The triphasic enhanced scans were obtained at 25s, 65s and 2-3min after the start of injection. In enhanced scan, the parameters were 120Kv, 240mAs, 5-10mm collimation, pitch =1:1. Two experienced radiologists assessed the TNM staging before operation byblind method. Multiple plane reconstruction (MPR) technique was adopted if necessary.The expression of COX-2 and nm23 were detected with immuohistochemistry and reverse transcription polymerase chain reaction(RT-PCR). Statistical analysis was performed with SPSS 10.0 software and statistically significant level was considered as "alpha equals 0.05".Results: l.On enhanced scan, the normal gastric wall presented monolayer structure in 28patients (41.8%), and 2/-³ layers in 39 patients (58.2%).2. All lesions could be accurately detected by Spiral CT. 3. In all patients, the accuracy of Spiral CT for T and N staging was 85.7% (57/67) and 86.6% (58/67), respectively, and the accuracy for Lauren classification was 95.5% (64/67) . Statistically significant difference existed between Spiral CT and pathologic diagnosis (P<0.001). 4. The COX-2 overexpression rate was 47.0% (39/83). And in the tumors with stageT3.4 and Ti₂, with and without lymph node metastasis, diffused and intestinal, stagelll+IVand I + II gastric carcinoma, the COX-2 Over-expression rates were79.l%(34/43)and54.l%(13/24),79.5%(31/39) and 57.1%(16/28),86.3%(38/44) and 39.1%(9/23,82.2%(37/45) and 45.5% (10/22),respectively, the differences were statistically significant in each of the groups (P <0.05).5.The low-expression rate of nm23-Hi in gastric carcinoma was 71.6%.And the low-expression rate of nm23-Hi in the patients without lymph node metastasis(89.2 % )and in stage I + II (90.9%)and in stage Ti₂(83.3 %) were much higher than those in the patients with lymph node metastasis(58.9%)and in stageIII+IV(62.2%)and in stageT3.4(58.4 % ),respectively, (P<0.05).Conclusion: 1. Enhanced Spiral CT scan was a credible examination in gastric cancer. It could well display the imaging features and the molecular pathologic basement of gastric carcinoma. 2. Spiral CT could differentiate the diffused type from intestinal type. 3. The overexpression of COX-2 was positively related to size, depth of invasion, lymph node metastasis and TNM stage in Spiral CT features of gastric carcinoma, which indicated that COX-2 can promote the multiplication, invasiveness and metastasis of gastric carcinoma. 4. The low-expression of nm23-Hi was negatively related to depth of invasion, lymph node metastasis and TNM stage in Spiral CT features of gastric carcinoma, which indicated that nm23-Hi can restrain the invasiveness and metastasis of gastric carcinoma. 5. Enhanced Spiral CT scan combined with pathology technique might improve diagnostic accuracy of invasion and metastasis and evaluation prognosis in gastric carcinoma.