| PrefaceThe invasion and metastasis of gastric cancer is the most essential reason that affect the prognosis of gastric cancer.Adhension , degradation and mobility are the three steps of invasion and metastasis of Carcinoma cells reported by liotta in 1986. From then on, a lot of adhesion molecules and degradation enzymes had been studied in vivo or in vitro about various human Carcinomas .Heparanase is an endoglycosidase which degrades the heparan sulfate (HSPG) , principal components of ECM but a substrate of the MMP, hepara-nase activity correlates with the metastatic potential of tumor cells. Two essential processes required for metastasis are neoangio genesis and tumor cell invasion of the basement membrane and extracellular matrix. HS is an essential Component of the extracellular matrixes of most tissues and is also a prominent component of blood vessels, which is essential for insolubility of the extracellular components, cell adhesion, and locomotion. Accordingly, cleavage of HS by heparanase enzyme may play a decisive role in extravsasion and invasion of tumor cells. So far, heparanase activity has been detected in various tumors and was found to correlate with their metastasis potential. Meanwhile heparanase may also contribute to angiogenesis by releasing the HS - bound growth factors such as bF-GF. bFGF is a potent angiogenic growth factor that requires heparin or HS for its biological activity mediated through tyrosine kinase signaling. The activity of bFGF is stringently controlled because it can be inactive in normal tissues and becomes activated on tissue injury, inflammation and tumor invasion. Heparanase enzyme possesses the ability to activate bFGF through structural modulation of the cell surface HS proteoglycan.It is essential step for invasion and metastasis that tumor cells leave the pri-mary tumor, so, adhesion molecules take the key role in maintaining the completion of tissues. E - cadherin is one of the most important adhesion molecules. E - cadherin contributes to an unit with its relating proteins, such asa - Cat, 3 - Cat and-y - Cat , which takes the key role in mediating the adhesion of cell -cell. MMP - 9 is the most important enzyme in the MMP family, whose main function is degradation of the extracellular protein such as type IV collagen, the major structural component of basement membrane, and then promotes the tumor cells mobile in ECM.In this study, we investigated heparanase, E - CD and MMP - 9 expression in gastric cancer tissues, as well as its clinicopathological significance, in particular the significance of their coexpression by RT - PCR and immunohistochem-istry.Materials and MethodsPatients; Fifty patients with gastric cancer who underwent gastrictomy in stomach department , Liaoning tumor hospital from February 2002 to may 2002. Together with the cancer tissues in 50 patients, adjacent normal gastric tissues in 41 patients were resected , Each sample was Snap - frozen and stored at -800c before extraction of RNA.RNA isolation and RT - PCR: Total cellular RNA was extracted from the tissues by TRIZOL reagent, in one - step. Then, changed RNA to cDNA by the process of reverse transcription and detected the expression of HPA, E - CD and MMP - 9 by PCR amplification, The PCR product underwent electrophoresis u-sing 2% agaroses, analyzed the electrophoretic images and calculated the values representing the expressive levels of mRNA.Imrnunohistochemistry; Using paraffin - embeddad tissue sections, immu-nohistochemistry was performed according to the S - P method.ResultsHeparanase mRNA expression. To search for the possible involvement of heparanase in the metastasis of human gastric cancers, the expression of hepara-nase mRNA was studied in 50 gastric cancer tissues and to adjacent normal gastric tissues , of the tissues from all 50 patients examined, 33 cancer tissues (60% ) and 41 adjacent normal gastric tissues ,12 samples (29. 3% ) give positive signals. The positive rate in cancer tissues was significantly higher than that... |
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