Study On Genes Related To Gastric Carcinoma Metastasis By LCM

IntroductionMetastasis is one of the most dominant features of malignant tumors and the key factor for survival of patients. But compared with the tumor etiology, the study on tumor metastasis mechanism is still in a very early stage. Metastasis is a complex pathologic course consisted of multiple stages and regulated by multiple genes. To understand the molecular mechanism of metastasis, analyzing the structure and expression of genes in tumor cells is definitely required. Tumor tissue is a three - dimension structure composed of multiple kinds of cells, the normal cells may influence the detection results. So it is very important to solve the cellular heterogeneity for tumor molecular pathology study. LCM is a technique developed recently, by which specific cells/cell may be seperated from tissue slides. It is a very important technique in molecular pathology and tumor genom-ics study for its success in solving the cellular heterogeneity.Gastric cancer is one of the most common malignant tumors in the world. Since the gastric carcinoma in western countries is usually detected in an advanced stage, the 5 - year survival rate is very low. Even in China and Japan, gastric carcinoma is the second most frequent cause of cancer death. Invasion and metastasis are main reasons for poor prognosis of gastric cancer, but the molecular mechanism of invasion and metastasis still remains unclear.The prognosis of gastric cancer patients has been improved by the standardization of surgical techniques and recent advances in multimodal adjuvant therapy. But there are no accurate or effective molecular markers for classification, biologic behavior and subclinical metastasis diagnosis, which hinder the progress of surgical therapy. It is very necessary to find some molecular markers for bio-logic behavior of gastric cancer and establish the standard of molecular classification, which may be very useful for surgical therapy of gastric cancer, too.The 5 - year survival rate of advanced gastric carcinoma remains around 50% , the main reason is the peritoneal recurrence occurs in about half of the cases after curative lymphadenectomy. It is generally accepted that the free cancer cells exfoliated from the lesions where tumors invades the serosa or lymph node capsules before surgical performance are the main reason in further development. Cytological examination of peritoneal washes is a specific method for assessing the presence of free cancer cells in peritoneal cavity, but it is not very sensitive. CES mRNA assessing is more sensitive than cytological examination, but there are some false - positive and false - negative results in it. It is necessary to find novel specific molecular markers.In this study, we established the LCM based molecular pathological system first. Then we analyzed the association between the expression of heparanase, RhoC and survivin genes and the progression and metastasis of gastric cancer. At last, we analyzed the association of heparanase and survivin and the peritoneal micrometastasis of gastric carcinoma.Materials and methods1. A limited number of normal gastric mucosa and gastric cancer cells were obtained by LCM and sujected to HF - WGA. The products were tested by PCR for several genes with different length fragments to examine the quality and effectiveness of amplification.2. A limited number of gastric cancer cells were obtained by LCM from frozen sections, ethanol or formalin fixed paraffin embedded sections and subjected to DNA PCR and RT - PCR to examine the influence of different sections on DNA and RNA analysis after LCM.3. Thirty patients who had undergone gastrectomy with lymph node dissection for gastric cancer without preoperative treatment were included in the present study. The neoplastic tissue, metastatic lymph nodes, and apparently unin-volved normal tissue were collected from each patient. Bulk tissues and LCM -captured " pure" cell groups were separately subjected to RT - PCR analysis with primers specific for heparanase.4. The ne...