| Background and goals: stomach cancer or gastric cancer is one of themost common cancers, and it is even more common in Asian countries, themorbidity and mortality of which in China are among the highest in the wholeworld. Hence, stomach cancer has become one of the most serious threats tothe public health in our country. The peak age of the onset of stomach canceris during the age from45to65, however, the summit of the cancer has beentrending younger currently. The main topic of the research is to make acomparison among the expressions of CystatinC, CathepsinB, EGFR in boththe young and old stomach cancer patients and trying to first understand thedifference between the occurring and development of both the young and oldpatients in terms of molecular mechanism and then further analysis therelationship with differentiated degree, clinical stages, lymphatic metastasis,etc. Through the investigation, the aim of the research is to provide theoreticalbasis and advice for the clinical diagnosis, treatment and prognosis.Materials and methodology: In this thesis,117excision samples, whichhave been diagnosed as patients with gastric carcinoma (not includingesophagogastric junction carcinoma) by North Sichuan Medical College, areselected as the object of the research. Among all the samples,52samples arefrom young patients (<35) and65samples are from old patients (>65); interms of gender,71samples are from men and46sample are from women. Dividing the samples from view point of symptoms,61samples are fromhigh-middle differentiated adenocarcinoma patients,56samples are from lowdifferentiated adenocarcinoma patients,46samples are from the patients,whose lump are larger than5cm, and71samples are from the patients, whoselump are smaller than5cm,41samples are from tumour infiltrating serosapatients,76samples are from tumour infiltrating serosa patients;49samplesare from lymphatic metastasis patients,68samples are from non-lymphaticmetastasis patients,16of which have been diagnosed as distant metastasis;Besides,15samples from high-level non-typical hyperplasia of gastric tissuepatients and15samples from normal appearing tissue are selected as controlgroups. In this research, immunocytochemistry method (S-P method) andin-situ hybridization method have been adopted to detect CystatinC,CathepsinB, EGFR, and the expression of mRNA, then trying to discovertheir relationship with gender, differentiated degree, depth of infiltration,lymphatic metastasis, size of lumps, distant metastasis and clinical stages, etc.Results:1. the positive rate of cathespin B, EGFR in the gastric cancertissue of young patient is significantly higher than which of old patients (P <0.05), while there is no obvious difference of expression of cystatin C;2. Thepositive rate of EGFR in the gastric cancer tissue of non-selected peoplesignificantly exceeds non-typical gastric proliferating tissue, and there is noexpression of normal appearing tissue. In the low differentiating group, thereis expression rise in the lymphatic metastasis group, infiltrating serosa groupand advanced stage of stomach cancer group (P <0.05).3. Cathespin B playsan important role in creating the difference of the positive expression rate, andthere is no expression of normal appearing tissue. In the low differentiatinggroup, the lymphatic metastasis group and the infiltrating serosa group, the expression of stomach cancer tissue is higher than old patients (P <0.01), andthere is a rise of expression among lymphatic metastasis and distantmetastasis among young patients.4. The expression level of cystatin Cdecreases while the deepening of lesion (P <0.05);5. The expression ofcystatin C decreases with the increasing of the expression of EGFR,exhibiting a negative correlation (r=-0.207, P <0.05); the expression ofcystatin B decreases with the increasing of the expression of cystatin C,exhibiting a more obvious negative correlation (r=-0.648, P <0.01);6. Theexpression of EGFR mRNA in the stomach cancer tissue is significantlyhigher than the corresponding expression in the non-cancer tissue (P <0.05),which is in accord with the expression of EGFR protein;7. The highexpression of cathespin B mRNA in stomach cancer, no expression innon-cancer tissue, which are in accord with the expression of protein;8. Theexpression of cystatin C mRNA in stomach cancer is higher than innon-cancer tissue, which are in accord with the expression of protein;9.Women form a larger proportion in young patients and are poorlydifferentiated, while men form a larger proportion in old patients and are well-differentiated.Conclusions: The expression of EGFR has a close relationship with thepathogenesis of stomach cancer. Hence, the detection the expression of EGFRin the stomach cancer tissue will contribute to distinguish the metastaticpotential of stomach cancer and then improve the detectable rate of earlygastric cancer. Cathepsin B can be used as one of the effective index ofdiagnosis of gastric cancer.The high expression of cathepsin B shows thatthere is maybe a lymphatic metastasis in young stomach patients. Theexpression level of cystatin C could be a reference indicator to evaluate the clinical stages of stomach cancer, especially for the young patients. Given thatthere are different clinic-pathological characteristics between young and oldstomach cancer patients, individualised diagnosis and treatment schemeshould be adopted to adapt the individual difference. |
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