| Objective:The purpose of this study was to investigate the relationship between MSI status and PD-L1 expression level and regional lymph node metastasis in gastric adenocarcinoma,and to elaborate the correlation with other clinicopathological features,and to explore the role of MSI status and PD-L1 expression level in the risk of regional lymph node metastasis in gastric adenocarcinoma.It provides a theoretical basis for the application of immunotherapy in the conversion therapy of patients with locally advanced gastric cancer due to regional lymph node metastasis in the future.Methods:This study collected 134 patients undergoing laparoscopic radical gastrectomy for gastric adenocarcinoma in the general surgery Department of the 940 Hospital of the Chinese People’s Liberation Army Joint Logistic Support Force from October2021 to September 2022.According to the postoperative lymph node metastasis of the patients,after the inclusion and exclusion criteria screening,The 120 patients who met the criteria were divided into two groups: lymph node metastasis group and no lymph node metastasis group.General data collected from the two groups were analyzed,including: Age,sex,tumor site,depth of invasion,tumor length diameter,clinical stage,degree of tumor differentiation,postoperative pathology,and the total number of positive lymph nodes.Meanwhile,the expression levels of MMR protein(MLH1,MLH2,MLH6,PMS2),PD-L1,CD4+,and CD8+ in tumor tissues were detected by immunohistochemistry.Univariate statistical analysis and multivariate logistic regression analysis were performed for various indicators in the two groups to identify independent risk factors associated with lymph node metastasis in the region of gastric adenocarcinoma.Results:1.In 120 cases of gastric adenocarcinoma,MLH1 protein was absent in 12 cases(10%,12/120).PMS2 protein deletion was found in 10 cases,the deletion rate was8.3%(10/120),and no deletion was found in MSH2/MSH6.The total deletion rate of MLH1,PMS2,MSH2 and MSH6 proteins was 13.3%(16/120)in 16 cases.MLH1 protein deletion accounted for 75%(12/16)and PMS2 protein deletion accounted for62.5%(10/16)of the total deletion rate.There were 6 cases of MLH1 and PMS2 protein deletion,and the total deficiency rate was 37.5%(6/16).Of the 92 patients with positive lymph node metastases(LN +),6 cases had MLH1 protein deletion,the deletion rate was 6.52%(6/92);7 cases had PMS2 protein deletion,the deletion rate was 7.6%(7/92);6 cases had MLH1 protein deletion,the deletion rate was 7.6%(7/92),and the 28 patients with negative lymph node metastases(LN-)had MLH1 protein deletion.The deletion rate was 21.4%(6/28),and the deletion rate of PMS2 protein was 10.7%(3/28)in 3 cases.2.In 120 cases of gastric adenocarcinoma,PD-L1 was positively expressed in 40 cases,with a positive rate of 33.3%(40/120).80 cases were negative,the negative rate was 66.6%(80/120).In LN(+)patients,there were 39 cases with positive expression of PD-L1,and the positive rate was 42.3%(39/92);in LN(-)patients,there was 1 case with positive expression of PD-L1,and the positive rate was 3.5%(1/28).3.In 120 cases of gastric adenocarcinoma,CD8+ was highly expressed in 45cases(37.5%,45/120).75 cases had low expression,and the low expression rate was62.5%(75/120).There were 78 cases with high CD4+ expression(65.8%,78/120)and 42 cases with low CD4+ expression(35%,42/120).In LN(+)patients,39 cases had high expression of CD8+,the high expression rate was 42.3%(39/92),58 cases had high expression of CD4+,the high expression rate was 63.0%(58/92).In LN(-)patients,there were 6 cases of CD8+ with high expression rate of 21.4%(6/28)and 20 cases of CD4+ with high expression rate of 71.4%(20/28).4.Univariate analysis showed that gender,age,tumor size,tumor site,lauren’s classification,CD4+,MSH2,MSH6,PMS2 had no significant correlation with lymph node metastasis in the region of gastric adenocarcinoma(P>0.05).CD8+,tumor stage,depth of tumor invasion,degree of tumor differentiation,MLH1 deletion,and positive MSI and PD-L1 were risk factors for lymph node metastasis in gastric adenocarcinoma region(P<0.05).5.Multivariate Logistic regression analysis showed that CD8+ high expression(OR=1.042,95%CI(1.003,1.083)),low differentiation degree(OR=2.825,95%,CI(1.198,6.659)),clinical stage(OR=2.825,95%,CI(1.198,6.659)]and PD-L1 positive expression [OR=0.374,95%,CI(0.144,0.970)] were independent risk factors for lymph node metastasis of gastric adenocarcinoma(P<0.05).Conclusion:1.High expression of CD8+,differentiation degree,clinical stage and positive expression of PD-L1 are independent risk factors for lymph node metastasis in gastric adenocarcinoma.2.The positive expression of PD-L1 may be used as one of the factors to predict the progression of gastric cancer and affect the prognosis,and provide theoretical basis for the application of immunotherapy in the conversion therapy of patients with locally advanced gastric cancer due to regional lymph node metastasis in the future. |
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