| Malignant tumour is the second cause of the main death of human. The morbility and mortality is gradually increasing. Cancer is now rising to the most common killing disease in industrialized countries. The gastrointestinal cancer is one of the most common malignancies. Thanks to the progress made in diagnostic and therapeutic techniques, the prognosis of patients with gastric cancer and colorectal cancer has improved in recent years, even about 20-50% of patients with no evidence of metastasis on the time of diagnosis have recurrences within less than 5 years after radical resection for the primary tumor. It indicates that these patients still had minimal residual tumour cells after surgery. The systemic micrometastasis is considered existence at the time of surgery. Ashworth detected circulating tumour cells in the blood stream firstly in 1869. More and more articles generated great enthusiasm in this research community. Despite of evidence of the prognosticvalue of micrometastases detection by immunochemistry, it is not routinely used in cancer staging protocols. It is due to the complicated way and low sensitivity. The sensitive PCR technique was used in the late 1980s. It has greatly facilitated the detection the occult cancer cells. A single cancer cell seeded can be detected among the 105-107 mononuclear cells. In principle, PCR amplification of tissue-specific mRNA offers several advantages over the protein or DNA based assay: 1. RNA is very unstable in the extracellular environment: its detection should suggest the presence of the cancer cells in the examined tissue or body fluid; 2.Although monoclonal antibody tests are becoming increasingly sensitive, they are not expected to approach the single-molecule detection capability of PCR tests; 3. Tissue-specific mRNA can indicate the presence of cancer cells despite a negative protein-based assay.The molecular detection of cancer cells in a population of nonneoplastic cells must target molecular determinants commonly expressed by tumour cells, but not by non-tumoral cells. Among these determinants, considering tumors of epithelial origin like those the GI tract, there is mRNA encoding for CEA and cytokeratins, which are not usually expressed by normal lymph nodes, circulating and bone marrow cells.Despite of the high sensitivity, the routine reverse transcriptase polymerase chain reaction (RT-PCR) has the limitations; 1. It cannot reflect the mRNA amount of the detected specimen; 2. It is easy to be contaminated due to the complicatedsteps. 3. False-positive PCR result may often be available due to the illegitimate trascription. Though the number of these transcripts in inappropriate cells is very low (estimated at one mRNA molecule per 100-1000 cells). Pseudogenes can also give rise to false-positive result. These problems were not overcome until the use of the Fluorescence Quantitive Polymerase Chain Reaction (FQ-PCR). This FQ-PCR system allows accurate quantification of initial template copy number, based on the fact that the cycle number at which the sample fluorescence exceeds the background level is correlated with the starting copy number.In the prospective study, 171 GI tumour patients were choosed to investigate the amount of CK19mRNA, CK20mRNA and CEA mRNA on different specimen, such as preoperative peripheral blood, intraoperative tumour drainage vein blood, peritoneal washes, immediate postoperative peripheral blood. The main objective is to evaluate the value of the CK19> CK20^ CEA mRNA detected the occult cancer cells in the blood stream and peritoneal washes with FQ-PCR. To study the interplay between epithelium and ECM dramatically altered; as a consequence, neoplastic cells are admitted to invade the basal lamina and the surrounding stroma. Observe the difference of MMP-9mRNA and uPAmRNA in carcinoma tissues and adjacent matched tissue, to demonstrate the effection of the MMP-9mRNA and uPAmRNA. Try to discover the relation between the expression of MMP-9mRNA /uPAmRNA in the tissues and the expression of the CKmRNA /CEA... |
PDF Full Text Request