Relationship Between MDSCs,Tregs,PD-L1 And Chemotherapy Efficacy And Prognosis Of Advanced Gastric Cancer

Objective: By studying the differential expression of myeloid-derived immunosuppressive cells(MDSCs)and regulatory T cells(Tregs)in peripheral blood cells at the initial diagnosis of patients with advanced gastric cancer before and after treatment,and the expression of Programmed death-ligand 1(PD-L1)in cancer status,analysis of their correlation with clinical data and efficacy of chemotherapy,and by following the patient’s disease progression time,the role of MDSCs,Tregs,PD-L1 in the tumor immune microenvironment in the efficacy and prognosis of advanced gastric cancer chemotherapy.The aim is to find specific monitoring indicators for the monitoring of chemotherapy efficacy and prognosis of patients with advanced gastric cancer.Methods: 1.Between August 2017 and August 2019,46 patients with advanced gastric cancer diagnosed in the First Affiliated Hospital of Shihezi University Medical College were included,and pathological tissue wax blocks,peripheral blood samples before and after chemotherapy were collected.Flow cytometry was used to detect the levels of MDSCs and Tregs before chemotherapy,and immunohistochemistry was used to detect the status of PD-L1 in cancer tissues.The relationship between the expression levels of MDSCs and Tregs before chemotherapy and the expression status of PD-L1 in tissues were analyzed.2.To analyze the relationship between the expression of MDSCs and Tregs,the expression of PD-L1 and the efficacy of chemotherapy before chemotherapy.And analysis of the correlation between the expression of MDSCs and Tregs and the expression of PD-L1.3.Flow cytometry was used to detect the expression levels of MDSCs and Tregs in peripheral blood after chemotherapy,and to analyze the correlation between the dynamic changes of MDSCs and Tregs in peripheral blood before and after chemotherapy and the efficacy of chemotherapy.4.Patients were followed up for progression-free survival.The effects of MDSCs and Tregs expression and PD-L1 expression status before chemotherapy on the prognosis of patients were analyzed.Results: 1.The levels of MDSCs and Tregs in peripheral blood of patients with advanced gastric cancer before chemotherapy,the status of PD-L1 in cancer tissues are positively correlated with the presence of distant metastases and TNM staging.That is,MDSCs,Tregs levels,and PD-L1 positive rates were higher in patients with distant metastasis or tumor TNM stage than those without distant metastasis or tumor TNM stage(P<0.05).It was not related to the patient’s gender,age,and tumor size(P>0.05).In addition,the level of MDSCs expression before chemotherapy was also positively correlated with tumor differentiation status(P<0.05).2.There was no correlation between the expression of MDSCs and Tregs in peripheral blood of patients with gastric cancer before chemotherapy and the efficacy of chemotherapy(P>0.05).The disease control rate of PD-L1 positive group in gastric cancer tissue was 12.5% and the disease control rate of PD-L1 negative group was 53.33%,with statistically significant differences(P<0.01),that is,patients with negative PD-L1 expression had better curative effect.In addition,the levels of MDSCs and Tregs in peripheral blood before chemotherapy were positively correlated with PD-L1 positive status in cancertissues(P<0.05).3.The expression of MDSCs and Tregs decreased after chemotherapy(P<0.01);the expression of MDSCs and Tregs decreased after chemotherapy in the disease control group(P<0.05),while the expression of MDSCs and Tregs increased after chemotherapy in the disease progression group(P<0.01).4.Before chemotherapy,the median PFS(12 months)in the low MDSCs group was 7 months longer than that in the high MDSCs group(5 months)(P<0.01);The median PFS(9 months)in the low Tregs group Compared with the high Tregs group(6 months),it was extended for 3 months(P<0.05),suggesting that the prognosis of MDSCs and Tregs with low expression was better.In addition,the median PFS of the PD-L1 negative group(13 months)was extended by 8 months compared with the median PFS of the PD-L1 positive group(5 months)(P<0.001),suggesting that the PD-L1 expression negative has a good prognosis.Conclusion: 1.Patients with decreased expression levels of MDSCs and Tregs and negative expression of PD-L1 had better chemotherapy efficacy.2.MDSCs 、Tregs and PD-L1 are associated with tumor prognosis.Patients with low MDSCs 、 Tregs expression and PD-L1 negative expression before chemotherapy have significantly longer disease-free progression,suggesting that peripheral blood MDSCs 、 Tregs and PD-L1 in tissues may be prognostic indicators for patients with advanced gastric cancer.