Expression And Clinical Significance Of PD-L1 Protein In Diffuse Large B Cell Lymphoma

Objective In order to provide theoretical basis for clinical immunotherapy,we detected the expression of PD-L1 protein in diffuse large B cell lymphoma(DLBCL)and analyzed the relationship between PD-L1 protein with the clinicopathological features of DLBCL and the prognostic factors including p53,c-myc,CD30,ALK and EBER.Methods EnVision immunohistochemical method was used to detect the expression of PD-L1 in 50 cases of DLBCL(experimental group)and 30 cases of proliferative tonsil(control group),and the relationship between the expression of PD-L1 protein in DLBCL and clinicpathological features were analyzed.In addition,the expression of p53,c-myc,CD30,ALK and EBER were detected by immunohistochemistry and in situ hybridization,and the rearrangement of MYC,BCL2 and BCL6 genes in paraffin embedded samples with highly expressed c-myc protein was further detected,and the relationship between the expression of PD-L1 protein and the above prognostic indicators was analyzed.Results The positive rate of PD-L1 protein was 42%(21/50)in 50 cases of DLBCL and 0%(0/30)in 30 cases of reactively proliferative tonsil.The expression of PD-L1 in DLBCL was significantly higher than that in the control group(P<0.001).In experimental group,the expression of PD-L1 was related to Hans subtype,the positive rate was significantly higher in non GCB subtype(70.6%,12/17)than that of GCB subtype(27.3%,9/33),and the difference was significant(P=0.003);while there were no correlation among the expression of PD-L1 protein with the gender,age,primary site,Ki-67 index,Ann Arbor stage,IPI score,serum LDH level,ECOG score or the B symptoms of patients,all the differences were not significant(P>0.05).2 The positive rate of p53 protein in 50 cases of DLBCL was 18%(9/50).There were no correlation among the expression of p53 protein with the gender,age,Hans subtype,primary site,Ki-67 index,Ann Arbor stage,IPI score,serum LDH level,ECOG score or the B symptoms of patients,all the differences were not significant(P>0.05).The protein expression of PD-L1 and p53 in the tumor cells had no correlation(rs=-0.101,P=0.487).3 The positive rate of c-myc protein was 14%(7/50)in 50 cases of DLBCL.There were no correlation among the expression of c-myc protein with the gender,age,Hans subtype,primary site,Ki-67 index,Ann Arbor stage,IPI score,serum LDH level,ECOG score or the B symptoms of patients,all the differences were not significant(P>0.05).The protein expression of PD-L1 and c-myc in the tumor cells had no correlation(rs=-0.125,P=0.386).4 The positive rate of CD30 protein in 50 cases of DLBCL was 14%(7/50).The expression of CD30 was related to Hans subtype,the positive rate was significantly higher in non GCB subtype(35.3%,6/17)than that of GCB subtype(3.0%,1/33),and the difference was significant(P=0.007);There were no correlation among the expression of CD30 protein with the gender,age,primary site,Ki-67 index,Ann Arbor stage,IPI score,serum LDH level,ECOG score or the B symptoms of patients,all the differences were not significant(P>0.05).The protein expression of PD-L1 and CD30 in the tumor cells had no correlation(rs=0.223,P=0.120).5 In the experimental group,The positive rates of ALK and EBER were 0%(0/50)and 4%(2/50).No further grouping and statistical analysis made due to poor positive cases.6 All the 7 cases of DLBCL with high expression of c-myc protein were DLBCL-NOS,immunophenotype showing double expression or triple expression.5 cases inside completed the detection of MYC,BCL2 and BCL6 split genes,no one was considered to be the High grade B-cell lymphoma: 1 case was only positive for MYC broken probe,2 cases were only positive for BCL6 broken probe,and the other 2 cases were not positive for all above genes.Conclusions 1 The potisive rate of PD-L1 in DLBCL is significantly higher than that in benign lymphoid tissues,especially in non GCB subtype DLBCL,which was an important theoretical basis for the immunotherapy of PD-L1 immunocheckpoint.2 There was no significant correlation between PD-L1 protein expression in DLBCL with the other clinicopathological features and prognostic indicators including p53,c-myc as well as CD30 protein,it is necessary to collect more clinical data and cases for statistical analysis to evaluate whether PD-L1 can be used as an independent evaluation indicator for the prognosis of DLBCL.Figure 5;Table 6;Reference 68...