Expression Differences And Its Clinical Significances Of MT-1,-2 And-3 In Esophageal Cancer

Objective:esophageal carcinoma, a kind of malignant tumor of digestive system, has posed a grave menace to the health of human beings, and the fatality rate of esophageal carcinoma is the seventh in that of malignant tumor. China is a country with high-incidence of esophageal cancer, and its mortality rate is the fourth in that of malignant tumor. Although we already have a number of extensive and depth researches about the mechanism of esophageal cancer, its concrete nosogenesis has not be identified. Studies indicate that the carcinogenesis of esophageal epithelium is a result of long-term cooperation of activations of oncogenes with inhibitions of anti-oncogenes.The metallothionein(MT), which was first identified in equine kidney in 1957, was a low molecular weight, high metal content, characteristic amino acid. MT fall into at least 4 subgroups, namely MT-1, MT-2, MT-3 and MT-4, and MT is thought to be involved in the homeostasis of essential metals, metal detoxification, free radical scavenging and many other areas.The studies of MT-1 and MT-2 have shown, MT-1 and MT-2 are most widely expressed isoforms in different tissues and are the best studies, in addition to have common biological function of MT, recent studies have shown that MT-1, MT-2 are closely related to the occurrence and development of malignant tumor. one bladder cancer research which was made by Saga and one breast cancer studies which was made by Zhang Rui-fen have shown that with the pathological grading higher, the expression rate of MT-1 and MT-2 positive correspondingly increased. Prompted with the rise of tumor malignancy and invasiveness, MT-1 and MT-2 expression level also will increase. In esophageal cancer, the study of Sun Xue-fei and others made used by immunohistochemical methods has indicated that the expression of MT-1, MT-2 was negatively related to esophageal cancer differentiation. Now we know that MT-3 have many same biological function with other isoforms, MT-3 also can inhibits cell proliferation besides this. MT-3 which was first validated to be capable of inhibiting the growth of neuronal cell in nervous system is not only Inhibit neuron growth and axon formation, involved in the regulation of neuronal regeneration, but also closely related with the occurrence of many cancers. Currently, many researches in Bladder cancer, prostate cancer, breast cancer and gastric cancer have shown that the expression levels of MT-3 are not the same in various malignant tumors. Such as in normal bladder tissue, there is no expression of MT-3, but MT-3 was expressed in all of the bladder cancer; In prostate cancer and prostatic intraepi- thelial proliferative lesions, MT-3 immunostaining differences were large, and some tumor cells and nerve cells, similar to the strong staining, while others no staining. Another study indicates that MT-3 gene in gastric cancer exist abnormal methylation. MT-3 is also closely related to the development of esophageal cancer, Tian Zi-qiang and others use immunohistochemical methods to study the expression of MT-3 in esophagus cancer, the conclusion have shown that MT-3 is over-expressed in esophageal cancer, in addition, the study of Tian Zi-qiang also have indicated that MT-3 gene exist abnor- mal methylation as well in esophageal by Restriction endonuclease analysis.This study observes the expression of MT-1, MT-2 and MT-3 in esophagus cancer by Western Blot Detection in order to study the expression differences of MT-1, MT-2 and MT-3 and the relationship between the expression levels of MT-1, MT-2 and MT-3 and the clinical pathological parameters.Method:1 Seventy fresh samples of tumor tissues and normal tissues from corresponding margin resected in Fourth Affiliated Hospital of Hebei Medical University between July, 2008 and July, 2009 were collected. The tumor center (removal of necrotic tissue) and peripheral tissues at least 5cm away from the tumor, and the tissue is recognized as a normal esophageal mucosa by pathological confirmation. With liquid nitrogen into frozen -70℃ refrigerator.2 Extract the whole cell protein of these tissues and detected the expression of MT-1, MT-2 and MT-3 by Western Blot. Use two-color infrared laser imaging system Odyssey scanning the film. Using Image J image analysis system to scan the optical density after the image is outputed, analysis the optical density of MT in esophageal cancer tissues and normal tissues. MT calculation esophageal cancer and the optical density of GAPDH in the light of protein optical density ratio and margin of normal tissue in the optical density of MT and GAPDH in the light of protein optical density ratios were used as the expression of MT.3 SPSS13.0 statistical software was employed to make a statistical analysis,T-test statistical method was used to analyze the expression of MT in the normal esophageal tissue and the cutting edge of tissue; the statistical method of variance analysis was used to analyze the expression of MT in esophageal cancer patients with clinical parameters.Result:1 The expression of MT-1, MT-2 in esophageal cancer was higher than normal tissue (t=5.214, P=0.000).2 The expression of MT-3 in esophageal cancer was higher than normal tissue (t=4.287, P=0.000).3 the expression levels of MT-1, MT-2 was enhanced with the increasing of the stage; (F=4.581, P=0.009); With the degrading of the differentiation the MT-1, MT-2 expression levels was get higher(F=11.451, P=0.000); But these is no differences between tumor site and MT-1 and MT-2 expression levels(F=0.253, P=0.778).4 the expression levels of MT-3 was enhanced with the degrading of the stage; (F=7.237, P=0.001); With the increasing of the differentiation the MT-3 expression level was get lower (F=5.357, P=0.010); But these is no differences between tumor site and MT-3 expression level(F=.038, P=0.963).Conclusion:1 The expression levels of MT-1, MT-2 and MT-3 in esophageal tissue was significantly higher than cutting edge of normal tissue expression. This indicates that the high expression of MT-1, MT-2 and MT-3 is closely related to the development.2 In less advanced and high-grade malignant esophageal tissues, the expression of MT-1, MT-2 tended to be high, This indicates that with the occurrence and further development of esophageal cancer MT-1, MT-2 expression level will increase as well; The over-expression or low-expression of MT-1, MT-2 have much positive significance for us to judge the degree of malignancythe; There was no significant difference between tumor site and MT-1 and MT-2 expression levels.3 In early stage and low-grade malignant esophageal tissues, the expression of MT-3 tended to be high, This indicates that MT-3 is close contact with the early onset and development of esophageal cancer, and tend to be over-expression. There is much positive significance for early diagnosis and treatment. The different expression level of MT-3 also help us to evaluate the degree of tumor malignancy; There was no significant difference between tumor site and MT-3 expression levels.