The Study Of The Expression Of XRCC1 And MGMT In Gastric Carcinoma

Background and Objective:Gastric carcinoma is the most common malignant tumor, It is of piratical importance to study gastric carcinoma's occurrence and development in order to make early diagnosis and decide treatment method to improve QOL of the patients. The normal function of a gene depends on its normal fabric. Cells are usually influenced by the environment, so DNA are easy to be injured. In order to maintain the genomic stability, cells must have effective repair systems. If any of them is deficient, the gene's injury could not be repaired and the mutations would accumulate in the genome. The genome become more unstable and as a result, proto-oncogenes were activated and cancer suppressor were inactivated. There are lots of DNA repair forms.Mismatch repair (MMR) system could repair base mismatch when DNA is replicating and ensure integrality of DNA. Damage reverse (DR) could repair DNA damage caused by alkylating agent and oxidizing agent and so on which is the simplest f o r m t o s u s t a i n t h e n o r m a l fr a me w o r k o f g e n e s . H o mo l o g o u s recombinational repair (HR) could repair DNA double-strand breaks caused by DNA metabolism, ionization radiation and active oxygen ,to sustain the integrality of genome and the normal expression of genes.Any abnormal expressions of DNA repair gene and their products may lead to the absence of DNA repair functions, accumulating of incorrect information and malignancy of cells. An immunohistochemistry method was used to detect the expression of MGMT and XRCC1 in different pathological lesions and different styles of gastric mucosa.To study their roles in carcinogensis,provide new theoretical foundation for forecasting the earli diagnosis,pre vention and clinical treatment,judging prognosis of gastric carcinoma.Materials and methods: The 100 gastric carcinomas paraffin specimens and 30 gastritis mucosa. were collected from the central hospital of Dandong ,The expressions of MGMT and XRCC1 protein were detected by immunohistochemistry (SP)method. Chi-square and Spearman is used for statistic analysis. Results:The positive expression rate of XRCC1 in gastric carcinoma being 89%(89/100)was significantly higher than those in surrounding epithelia being 45%(45/100)and in non carcinoma gastric mucosa (NCGM) being 30 % (9/30)(P<0.05), while there was no significantly difference between the two later (P>0.05) The positive expression rate of MGMT was 43%(43/100)and those in surrounding epithelia was 38%(38/100),there was no significantly difference between them,while they were significantly higher than those in non carcinoma gastric mucosa (NCGM) being13.3%(4/30)(P<0.05).Conclusions: 1.The expression of XRCC1 protein was high in gastric carcinoma,The expression of MGMT protein was also high in gastric carcinoma , The abnormal expressions of XRCC1 and MGMT protein indicate that there are many DNA damage repair forms in gastric carcinoma. Detect the expressions of these protein may be helpful to diagnose gastric carcinoma.2. The expressions of MGMT and XRCC1 were significantly correlated with lymph node metastasis infiltrative deepness(P<0.05), The expressions of MGMT and XRCC1 play important roles in gastric carcinoma's metastasis and infiltrative deepness.