Expression And Clinicopathological Significance Of APOBEC3B And PD-L1 In Nasopharyngeal Carcinoma

Objective:The aim of current study is to detect the expression of Apolipoprotein B m RNA-editing enzyme catalytic polypeptide-like 3B(APOBEC3B)and Programmed cell death 1 ligand 1(PD-L1)in nasopharyngeal carcinoma tissues and the influence on the prognosis of patients.Methods:Cases of nasopharyngeal biopsy in Fujian Medical University Union Hospital from June 2007 to January 2019 were collected,and a total of 176 cases with pathological diagnosis of non-keratotic cancer and complete follow-up data were selected.Clinical data of the patients were collected.The expression of APOBEC3 B and PD-L1 in nasopharyngeal carcinoma was detected by immunohistochemical staining.Univariate analysis and multivariate survival analysis(COX regression analysis)were used to determine the influence of APOBEC3 B,PD-L1,gender,age,T stage,N stage and M stage on the prognosis of NPC patients.Results:(1)APOBEC3B was expressed in tumor cytoplasm.The median was used as the cutoff value to divide the APOBEC3 B high-expression group(A3B-H)and the APOBEC3 B low-expression group(A3B-L).There were 77 cases of A3B-H and 99 cases of A3B-L.There was no significant difference in the expression of APOBEC3 B in different gender,age and T,N and M stages(P > 0.05).The percentage of PD-L1 positive cells was 5%,and the PD-L1 positive rate was 53.4%(94/176).There was no statistically significant difference in the expression of PD-L1 in groups of different genders,ages and T,N and M stages(P > 0.05).(2)Spearman correlation analysis showed that the expression of APOBEC3 B was positively correlated with that of PD-L1(P = 0.021,r = 0.173).(3)The results of univariate analysis showed that N stage,M stage,high expression of APOBEC3 B were correlated with progression-free survival time(PFS)of patients with nasopharyngeal carcinoma(all P values < 0.05).There was no significant correlation between gender,age,T stage,the expression of PD-L1 and PFS(all P values > 0.05).There was a correlation between gender,T stage,M stage,high expression of APOBEC3 B and overall survival time(OS)(all P values < 0.05).There was no significant correlation between age,the expression of PD-L1,N stage and OS(all P values were > 0.05).(4)The results of multivariate survival analysis showed that high expression of APOBEC3 B,N stage and M stage were independent influencing factors of PFS in patients with nasopharyngeal carcinoma(all P values < 0.05).High expression of APOBEC3 B,gender and M stage were independent influencing factors of OS in patients with nasopharyngeal carcinoma(all P values < 0.05).Conclusion:(1)High expression of APOBEC3 B protein in cancer tissues was a risk factor for tumor recurrence or metastasis in patients with nasopharyngeal carcinoma and reduced the overall survival time,which could be used as an indicator to evaluate prognosis.(2)The expression of APOBEC3 B in nasopharyngeal carcinoma was positively correlated with the expression of PD-L1,suggesting that APOBEC3 B may influence the tumor immune microenvironment.(3)The expression of PD-L1 protein in nasopharyngeal carcinoma has no significant correlation with tumor recurrence,metastasis and overall survival time in patients.