Expression And Clinical Significance Of Mismatch Repair Proteins MLH1,MSH2,MSH6 And PMS2 In Patients With Distal And Proximal Gastric Cancer In Qinghai

Objective :(1)To analyze the expression differences of mismatch repair proteins MLH1,MSH2,MSH6 and PMS2 in patients with proximal and distal gastric cancer in Qinghai.(2)Correlation analysis of the expression of mismatch repair proteins MLH1,MSH2,MSH6 and PMS2 with age,gender,TNM stage,histological grade and pathological type in patients with proximal and distal gastric cancer in Qinghai province.Methods: A total of 169 cases of proximal and distal gastric cancer were collected from the affiliated hospital of Qinghai university from December 2016 to October 2018,including 60 cases of proximal gastric cancer and 109 cases of distal gastric cancer.Immunohistochemical method(IHC)was used to detect the expression of four mismatch repair proteins MLH1,MSH2,MSH6 and PMS2 in gastric cancer tissues,and chi-square test was used to analyze their differential expression in proximal and distal gastric cancer and its correlation with clinical pathological characteristics and clinical significance.Results: 1.There was no statistically significant difference in the expression of the mismatch repair proteins MLH1,MSH2,MSH6 and PMS2 in proximal and distal gastric cancer(P>0.05).2.There were differences in the expression of PMS2 in gastric cancer between TNM staging,Lauren typing,nerve invasion and vascular invasion(P<0.05,with P values of 0.020,0.040,0.022,0.042 and 0.011).Among patients with gastric cancer whose expression of PMS2 was absent,T2 >T3>T1>T4,N0>N3a=N3b>N1=N2,intestinal type>diffuse type> mixed type;Nerve invasion: negative> positive,angioma thrombus: negative > positive.Among the patients with normal expression,T3>T2>T4>T1,N0> N2> N3a> N1> N3 b,diffuse type > mixed type> intestinal type,nerve invasion:positive > negative,angioma thrombus: positive >negative.There was no significant difference in gender,age,differentiation and plasma cell infiltration.3.The difference of MLH1 expression with age and vascular infiltration was statistically significant(P<0.05,P values were 0.003 and 0.041).Among the gastric cancer patients with MLH1 expression deficiency,all 7 patients were aged 60 years old,and the angioma thrombus:negative > positive.Among gastric cancer patients with normal MLH1 expression,Conclusion the opposite;There were no significant differences in gender,TNM stage,Lauren type,nerve invasion,and plasma cell infiltration.4.There were differences in the expression of dMMR in gastric cancer between TNM staging(P<0.05,with P values of 0.001),The same relult in distal gastric cancer(P<0.05,with P values of 0.001).Conclusions: 1.Both proximal and distal gastric cancer are more common in men,and the incidence of distal gastric cancer is higher in women.Proximal gastric cancer mostly occurred in the elderly group,while distal gastric cancer mostly occurred in the younger group;2.There was no difference in the expression of mismatch repair proteins MLH1,MSH2,MSH6 and PMS2 in the gastric cancer tissues of proximal and distal gastric cancer;3.Patients with gastric cancer whose PMS2 expression was absent,the proportion of patients with T2,N0,intestinal type and nerve invasion negative,and angioma thrombus negative was relatively high;4.Among the gastric cancer patients with MLH1 expression deficiency,the proportion of patients aged over 60 years,angioma thrombus negative is relatively high;5.The patients with dMMR has a earlier stage,especially in distal gastric cancer.