The Expression And Significance Of CDX2 Protein And MUC2 Protein In Intestinal-Type Gastric Carcinoma And The Evolution Of Precancerous Lesions

Aim:The gastric cancer is the second most common malignant tumour in our country.The intestinal metaplasia(IM) in gastric mucosa especially type III IM is cosely related with gastric cancer.The causes and development of IM are not clear at present.The bile reflux is considered as one of the causes of IM,but the mechanism is not sure.This study was to investigate the coexpression of CDX2 and MUC2 in intestinal-type gastric cancer and the evolution of precancerous lesions and its clinical significance.Methods:95 cases gastric mucosa biopsy were selected including 10 cases with chronic superficial gastritis(CSG) without IM;30 cases with CSG and IM including 19 cases dignosised as CSG with bile reflux,12 cases dignosed as CSG without bile reflux; 21 cases with chronic atrophic gastritis(CAG) with IM;4cases with atypical hyperplasia; 20cases with intestinal-type gastric cancer(GC) and 10 cases after subtotal gastrectomy. HP infection was detected using Warthin-Starry bacterium staining method. Alcian blue/high iron diamine was used to classify IM.The IM was classified into typeⅠ,typeⅡand type III according to El-Zimaity's method.The expression of CDX2 and MUC2 protein was assessed with monoclonal antibody S-P immunohistochemistry.Results:CDX2 was all expressed in a nuclear pattern whereas MUC2 showed cytoplasm reactivity. There was no positive expression of CDX2 and MUC2 in CSG without IM.The positive rates of CDX2 protein were 70.66% in CSG with IM,52.38% in CAG with IM,30% in GC.The positive rate in CSG with IM was significant higher than that in GC(p<0.01);the positive rates of MUC2 were 46.66% in CSG with IM,66.66% in CAG with IM,80.0% in GC.The positive rate in CSG with IM is lower than that in GC(P<0.05). The positive rate of Hp in CSG with IM group(70.33%) was higher than that in CSG without IM group(20%),CAG with IM group (42.86%),GC group(52.83%).And the positive rate of CDX2 in positive Hp group was higher than that in negative Hp group in each group (p<0.05).The positive rates of CDX2 protein in IM caused by CSG with bile reflux was much higher than that in CSG without bile reflux (89.74%VS54.54%),but only one in ten has positive expression in patients after subtotal gastrectomy.The expression of CDX2 and MUC2 was different in different subgroup of IM.The positive rate of CDX2 in typeⅠIM was 88.23%,higher than that in typeⅢIM(54.54%,P<0.05).The positive rate of MUC2 in typeⅠIM was 23.52%,lower than that in typeⅢIM(81.81%,P<0.01).The positive rate of CDX2 and MUC2 was no sinificant difference between typeⅠIM and typeⅡIM or typeⅡIM and typeⅢIM. The relativity had been found between CDX2 expression and MUC2 expression in CSG with IM and GC groups.Conclusions:①The ectopic expression of CDX2 is related with the development of IM in gastric mucosa which may be one of promoter genes of IM.(②The bile reflux to the stomach for a long time may switch on CDX2 gene,which trigger the initiation of IM in the stomach.③The infection of Hp is associated with the procedure of IM,The ectopic expression of CDX2 may be one of promoter genes.④MUC2 gene expression markedly increases in the formation of gastric cancer especially in the procedure from IM to gastric cancer.⑤The negative expression of CDX2 protein and the positive expression of MUC2 protein may represent a marker of tumor progression in early gastric cancer and the detection of CDX2 and MUC2 may help the diagnosis of early gastric cancer.