Expression And Clinical Significance Of MEG8 And TGM2 In Gastric Cancer

ObjectiveGastric cancer is one of the common malignant tumors.The incidence and mortality rate are among the highest in China and the world.There is still a lack of early diagnosis,treatment and prognosis-related gene targets for gastric cancer.Transglutaminase-2(TGM2)plays a driving role in the development of multiple cancers and is considered to be a key cancer cell survival factor;Maternal expression gene 8(MEG8)shares the maternal expression gene 3(MEG3)locus DLK1-DIO3.MEG3 is associated with tumorigenesis,development,metastasis,and chemotherapy resistance.MEG3 plays an important role in regulating the progression of gastric cancer.the expression and clinical significance of MEG8 in gastric cancer remains unclear.in this study,the expression of MEG8 and TGM2 in surgical specimens and adjacent control tissues of gastric cancer patients was examined to explore its expression and clinical significance in gastric cancer tissues.Method(1)In this study,30 patients with gastric cancer were surgically removed from january 2018 to january 2019 in the general surgery department of the east area of qingdao municipal hospital.gastric cancer tissue and adjacent tissue specimens were removed(the distance of the adjacent tissue was more than 5 cm from the edge of canceration).Patients were not treated with radiotherapy and chemotherapy before operation,and the medical records were complete.In the course of operation,after the surgical specimens were isolated from the body,the sterile tissue scissors were used to obtain the tissue specimens about 0.5*0.5*0.5cm in size.The samples were stored in EP tube with RNA sample preservation solution in advance(tissue samples were completely immersed in RNA sample preservation solution).After storage at 4°C for one night,discard the waste liquid and store the specimens in-80°C refrigerator.(2)The expression of MEG8 and TGM2 in 30 pairs of gastric cancer and its adjacent tissues were detected by quantificational real-time polymerase chain reaction(QRT-PCR).The age,sex,stage of gastric cancer,differentiation and metastasis were collected.(3)Using SPSS version 19.0software for statistical processing,according to the type of data,using different statistical methods to analyze,continuous variables using t test,classification variables using c2test,ordered variables using regression analysis,using Kaplan-Meier method to draw survival curve,using log-rank test to analyze the correlation between TGM2 expression andsurvival status of gastric cancer patients.P <0.05 was statistically significant.Results(1)In 30 pairs of gastric cancer tissues and their corresponding paracancerous tissues,the expression of MEG8 in gastric cancer tissues was lower than that in paracancerous tissues(0.462±0.082 vs.1.048±0.149),and the expression of TGM2 in gastric cancer tissues was higher than that in paracancerous tissues(1.02±0.143 vs.0.742±0.083),and the difference was statistically significant(P <0.05).(2)MEG8 expression was related to age,clinical stage(P <0.05),not to sex,tumor location,differentiation degree,tumor size,lymphatic metastasis and distant metastasis(P >0.05);TGM2 expression was related to clinical stage(P =0.001),and there was no significant difference in age,sex,tumor location,differentiation,tumor size,lymphatic metastasis and distant metastasis.(3)Statistics taken from Oncomine database of 85 patients with gastric cancer,the expression of TGM2 gene in gastric cancer and its corresponding normal tissue,the expression of TGM2 in gastric cancer tissue was significantly higher than that in normal gastric mucosa(P <0.001);log-rank test results showed that the expression of TGM2 was not related to the survival status of gastric cancer patients(P =0.607).Conclusions(1)MEG8 expression level is down-regulated in gastric cancer tissues,and the expression level decreases with the increase of clinical stages,which may become a new marker for clinical diagnosis and evaluation of gastric cancer.(2)TGM2 expression level increased in gastric cancer tissues,the higher the expression level,the higher the clinical stage,which can be used as a potential target for the diagnosis and treatment of gastric cancer;there was no significant correlation between the expression of TGM2 and the survival time of gastric cancer patients.