Expression Of ST2Protein In Human Gastric Carcinoma And Its Correlation With Gastric Cancer Development

【Background】Gastric cancer is malignant cancer that threats people’s healthseriously. It is one of the common malignant tumors in the worldwide.The rates of the incidence and the mortality are high.The rates of earlydiagnosis and the curing are very low. With the development of tumorimmunology and molecular biology research, scientists have believedthat the tumors are correct to immunology. On the one hand, theimmune system has immune surveillance and immune responses totumors; on the other hand, tumors can evade immune systemsurveillance. It has been confirmed that there are different antigencomponents between tumor cells and normal tissue cells. It may betherapeutic effect for patient to detect the different antigen componentsof cancer cell or to induce cancer antigens responses to cancer byimmune system. Although the function of immunosuppressive subgroupcells and inhibitory molecules have been recognized. The mechanismsof tumor immunity and immune escaping have made some progress.butthe mechanisms of tumor immunity and immune escaping are stillexploring. It is important to found tumor antigen for diagnostic andtherapeutic, especially the negative regulatory immune cells ormechanism of immune molecules in the tumor immune escape. ST2is amember of TOLL/IL-1receptor family; it has the immune regulation faction. It is similar to other IL-1R family members that can inducecells signal transduction. ST2protein plays a key role in function of theTH2cells. ST2protein is involved in inflammatory diseases, trauma,the pathogenesis of allergic diseases, autoimmune diseases,cardiovascular diseases and cancer, et al. We have studied that ST2protein can bind to polypeptide PIII which is the receptor of theGC9811-P cells that are gastric cancer cell with peritoneal highlymetastatic. We Speculated that ST2protein collect to peritonealmetastasis of gastric ST2cancer. This subject will examine the impactof the ST2protein on the development of gastric cancer.【Objects】1.We investigate the expression of ST2protein in gastric and neargastric cancer. In order to clarify the relationship betweenclinicopathological parameters and gastric carcinoma.2. We study the effect of ST2protein in gastric development.【Methods】1.We collected52cases including gastric cancer and near gastriccancer,and lymph node metastas and without metastasis lymph nodetissue from2006to2010years in Xi Jin hospital affiliated of TheFourth military medical college, in additions to we bought tissuemicroarray chips (including cancer, near gastric cancer, lymph nodemetastasis and without metastasis to lymph node)178cases from XianAoMei Biotechnology Co. Total number of cancer were230cases,adjacent noncancerous were89cases, lymph node metastasis were49cases, without lymph node metastasis were15cases. We detected ST2protein expression in gastric carcinoma and adjacent cancer tissue, lymph node metastasis and without metastasis lymph node tissue byimmunohistochemical.2.The location and the expression of ST2protein in sections ofgastric tissue and adjacent were detect by immunofluorescence.3.We collected12fresh surgical specimens of patients with gastriccancer in Xi jin Hospital affiliated The Fourth Military MedicalUniversity, cut out the cancer and matching adjacent normal tissues；and cultured gastric cancer cells MKN45, SGC7901, AGS and normalgastric mucosal cells EGS; extracted protein and done the Westernblot to analysis ST2protein expression.4.We used SPSS13.0statistical software to analyze the relationshipbetween ST2protein expression and patients with various clinicalpathological parameters.【Results】1. The ST2protein express mainly in the cytoplasm, partly in thecell membrane. In the experimental group，the ST2protein positive rateof230patients with gastric carcinoma is39.1%(90/230), the positiverate of89cases of cancer adjacent tissues is60.7%(54/89), the differencewas significant ststidtically(P<0.05); The positive rates of ST2protein inwell-differentiated adenocarcinoma is76%, moderately differentiatedadenocarcinoma is47%,poorly differentiated adenocarcinoma is24%, mucusadenocarcinoma is19%. The difference positive rates of ST2proteindifferentiated adenocarcinoma are statistically significant(P<005);the expressionof ST2protein has no relation with age and sex(P>0.05);The positive rates ofdifference TNM staging betweenⅠII(46.9%) and III IV phase(26.4%) arestatistically significant(P<0.05).The positive rates of ST2protein in lymph node metastasis is53%,The positive rates of without lymph node metastasis is0%,thedifference was statistically significant(P<0.05).2.The ST2protein expression is no relation to patient’s gender and age(P>0.05).3.Western blot results showed that two isoforms of ST2protein, sST2andST2v are expression in gastric carcinoma and adjacent noncancerous tissue.Gastric cells and normal gastric cells express ST2protein also.【Conclusion】The expression of the ST2protein is related to the degree of gastriccancer differentiation and lymph node metastasis and Clinical TNMstage. ST2protein may regulate immunizaiton responses indevelopment of gastric cancer.