The Status Of PD-L1 Expression And TILs Among ESCC Patients In China And Changes After Radiation And Chemotherapy

Objective:PD-L1 protein is broadly expressed on some solid tumors,and it has some clinical value.What’s more,tumor infiltrating lymphocytes are also one of significant character.But little data supports their expression and clinical value in esophageal squamous cell carcinoma.So this study aim to examine the expression of PD-L1,CD8+T cells and PD-1+T cells by immunohistochemistry in esophageal squamous cell carcinoma.Moreover,PD-L1 expression and tumor infiltrating lymphocytes may change after chemotherapy and radiation.And this study aim to analyze the influence of chemotherapy and radiation on the expression of PD-L1,CD8+T cells and PD-1+T cells in esophageal squamous cell carcinoma.Methods: We collect 240 esophageal squamous cell carcinoma patients who underwent esophageal cancer radical operation between January 2009 and January 2015.Of these 240 patients,136 patients are classified into surgery-only group and 104 patients are classified into neoadjuvant chemoradiotherapy group.Then we collected the postoperative specimens of these patients,and detected the expression of PD-L1 protein,PD-1+T cells and CD8+T cells by immunohistochemical staining.We analyzed the relation between the expression of PD-L1 protein and other clinicopathological parameters.Then we analyzed the influences of radiation and chemotherapy on the expression of PD-L1 protein,PD-1+T cells and CD8+T cells.We also analyzed the relation between these clinicopathological parameters and the prognosis.All these statistical analysis were accomplished by SPSS 17.0 software.Results: Of these 240 patients with esophageal squamous cell carcinoma,the ratio of positive expression of PD-L1 protein is 46.3%,and that of negative expression of PD-L1 protein is 53.7%.The infiltration degree of CD8+T cells with grade 0,1,2,3 is 19.6%、57.9%、20.8%、1.7%.The infiltration degree of PD1+T cells with grade 0,1,2,3 is 40.4%、41.3%、15.4%、2.9%.And the ratio of patients with positive expression of PD-L1 protein and the infiltration of CD8+T cells whose grade is above 1 is 37%.There is no significant relation between the positive expression of PD-L1 protein and clinicopathological parameters including sex,TNM stage,tumor location and histology differentiated degree.The infiltration degree of CD8+T cells positively correlates with positive expression of PD-L1 protein,and the infiltration degree of PD1+T cells negatively correlates with positive expression of PD-L1 protein.Compared with the surgery-only group,there is an increase in the PD-L1 expression in NACRT and NCT(≥3 cycles)groups.There is no obvious changes of the infiltration degree of CD8+T cells and PD1+T cells after radiation or chemotherapy.In surgery-only group,we find a correlation between TNM stage,positive expression of PD-L1 protein and poor prognosis.And COX analysis shows TNM stage and the expression of PD-L1 protein are independent prognostic factors.Conclusions: In this study,we find a high positive expression of PD-L1 protein and a high infiltration degree of TILs,especially CD8+T cells.And the expression of PD-L1 protein is positively related with the infiltration degree of CD8+T cells and negatively related with the infiltration degree of PD1+T cells.We also find an increase of the PD-L1 expression after concurrent chemoradiotherapy and a long period of chemotherapy.At last,we also find a relation between the positive expression of PD-L1 protein and poor prognosis and it is an independent prognostic factor.