A Novel Approach For The Detection Of Gastric Carcinoma-associated MG7-Ag By Serum Quantitative Immuno-PCR And Its Significance

Gastric cancer is a common gastrointestinal malignancy, whose mortality rate is the second in all the malignant tumors. It is very important for treatment and prognosis of gastric cancer to detect and diagnose early. The early diagnosis is restricted because of the poor sensitivity and specificity of previous markers such as CEA and CA50. by serum screening in diagnosis gastric cancer. Therefor, there is great significance to look for a new specific antigen for the diagnose and treatment of gastric cancer.The professor Fan in our lab developed a series of stomach monoclonal antibodies in the 1980s, Named MGAbs( especially MG7), which have a higher specificity and sensibility for the gastric cancer. Our lab established ELISA and immuno-PCR by detecting MG7 antigen in serum successively,The immuno-PCR improved the sensitivity and specificity of gastric cancer diagnosis significantly. However, the immune PCR can not achieve precise quatification and can not distinguish gastric cancer progression too, since it is only half-quantifying and qualitative analysis and its specificity is restricted . The real-time polymerase chain reaction (PCR) technology help us resolve the difficult which acheive the quantitation precisly.There are many kinds of MGAgs, and they are not identified yet.We fond that the monoclonal antibody sandwich method of MG7 and MGb2 can detect the MGAgs in the blood.Therefor,in the precent, we aimed to detect the MGAgs in the blood percisely ane quantitativly by quantitative immune PCR technology in oder to provide the theory for the diagnose early of gastric cancer.[objective] 1. To establish a new method to detect the gastric cancer MGAgs by quantitative immune PCR in the serum. 2.To quantify the MGAgs in serum of the patients with gastric cancer and normal healthy people.3 To analyses the serum MGAgs and to provide support for early diagnosis of gastric tumors.[method] 1.To recover hybridoma cell of MG7 and MGb2 and to prepare the monoclonal antibody of MG7 and MGb2. 2.To choose the suitbale plasmid and to label the plasmid and MG7Ab respectivly using the enzyme-linked immunosorbent.3. To detect the content of MGs antigen in the blood of gastric cancer by the real time immune-PCR technique.[results] The tubes of PCR which are polypropylene materials as a vector have a good adsorbability to MGb2 antibodies and can be used for the immune response as a carrier protein adsorption .Otherwise, it is a good, stable system for the combination of MG7 antibodies and MGb2 antibody with MGAgs. We had established a quantitative immune PCR method which had a better stability and had a higher sensitiity and specificity for the gastric cancer diagnosis. The relative MGAgs content in 50uL serum, gastric cancer is 21890±6579 MKN45 cells, healthy controls is 2844±914 MKN45 cells. The difference between the two groups is signifcant and there is statistics significance (P < 0.01 ).[conclusion] Using the real time immuno-PCR can detect the content of MGAgs in serum ,which can provide great value for the early warning of gastric cancer.