| IntroductionAt present, gastric carcinoma is one of the most incidence and mortality rate malignant tumors in China. Tumor cell is characterized by unlimited growth, uncontrolled infiltration and metastasis, which might be the most important reason why gastric cancer has been always met with therapeutic failure and resulting death. The growth, infiltration and metastasis of tumor cells are regulated by some oncogenes and tumor suppressor genes. In the course of metastasis, inactivation and decreased expression of metastatic suppressor genes play an important role in the progression of cancer - genesis besides the activation of pro-tooncogene, inactivation of anti - oncogene, abnormal intercellular adhesion and expression disturbance between metallo proteinases(MMP) and its inhibitor.KAI1 gene located in chromosome 11p11. 2 Bclongs to member of trans-membrane protein 4 superfamily (TM4SF) , encoding a cell membrane glycopro-tein,which mostly exists in the surface of white cells and other tissue cells. Some motif of KAI1 promoter can bind with many transcription factor, suggesting a complexity of regulatory mechanism in gene expression. It has been thought that KAI1/CD82 exert an inhibition on many tumors'metastasis resulted from its influence on cell movement, metastasis and proliferation.Steeg et al firstly separated and identified a tumor suppressor - associated gene named nm23 ( non metastasis 23 gene) classified as three subtypes, among which expression level of nm23 - H1 was associated closely with cancerous cells' metastasis. nm23 encodes a active protein of nucleoside - diphosphate kinase ( NDPK) , which play an important role in tumors' proliferation, differentia-tion, invasion and metastasis because of the regulation of cell metabolism by influencing microtubular polymerization and G - protein mediated signal transduc-tion pathwayThis study was designed to compared the expression of tumor suppressor gene KAI1/GD82 and metastatic suppressor gene nm23 in gastric cancer tissues , and hoped to find a predicted molecular marker for infiltration and metastasis of gastric cancer to judge the prognosis of gastric cancer and provide a scientific foundation for clinical therapeutic application.Materials and MethodsSpecimensEighty - seven cases of paraffin - embedded specimens of gastric cancer were derived from Liaoning province Tumor Hospital and No. 1 Hospital of China Medical University spanning the duration from July 2002 to June 2003, specimens include male 60 cases, female 27cases (mean 56 years old) , 5 cases of early gastric cancers (EGC) , 12 medium and70 late gastric cancers, 65 gastric cancers with lymph node metastasis, the other 22 without lymph node metastasis. Primary gastric cancerous, borderline and metastatic lymph node paraffin -embedded specimens of each patient were obtained to prepare 4 - micron continuous sections diagnosed by two senior pathologists.Reagent and instrumentsRabbit anti - human kail polyclonal antibody ( 1:50) and mouse anti - human nm23 - H, monoclonal antibody (1:100) were bought respectively from Santa Cruz and Zhongshan Biotechnology Company Ltd, Beijing. PV - 9000 kit from Zhongshan Biotechnology Company Ltd, Beijing.Evaluation of ImmunostainingPositive kail and nm23 - H1 immunostaining were located in cytoplasm, displaying dark brown. The evaluation of immunostaining was according to the percentage of positive cells from 5 randomly selective high power fields of each section, in each one of which 200 cells were counted, the degree of immunostaining was graded as follows: positive ones in counted cells: negative ( - ) ,positive rate <5% ; ( + ) , 5% -25% ;( + +), 25% -50% ;( + + +), > 50%.Statistical AnalysisStatistical analysis was performed using chi - square test. P < 0. 05 was considered as statistically significant.ResultsExpression of kAI1 and nm23 - H1 protein in gastric cancersPositive expression rate of KAIl 1 protein was 69% in gastric cancers, significantly lower than in para - cancerous gastric muc... |
PDF Full Text Request