Meta-Analysis Of The Relationship Between The Expression Of PD-L1 And The Pathological Characteristics And Prognosis Of Oral Squamous Cell Carcinoma

Objective: To evaluate the correlation between PD-L1 expression and the prognosis and clinicopathological characteristics of patients with oral squamous cell carcinoma(OSCC)through meta-analysis,providing a reference for clinical evaluation of prognosis.Methods:Search Pub Med,scientific database,scientific network,environmental database,Cochran library and CNKI database to find the correlation between PD-L1 expression and clinicopathological characteristics and total survival(OS)of OSCC patients.According to the relative risk(RR),hazard ratio(HR)and 95% confidence interval(CI),the correlation strength of PD-L1 expression with clinicopathological characteristics and OS in OSCC patients was evaluated.Results:1.The preliminary literature search produced 163 studies,and finally 33 studies were included in this study,with a total of 3921 patients.Twenty studies provided data on the relationship between clinicopathological characteristics and PD-L1 expression in patients with OSCC,and 21 studies provided data on the relationship between PD-L1 expression and overall survival(OS).2.In the included study,21 studies reported OS in patients with OSCC.Overall analysis showed that there was no significant correlation between PD-L1 positive expression and OS in patients with OSCC(HR=0.97,95%CI=0.80～1.18,P=0.75).3.4 studies have reported disease specific survival(DSS),and the results show that there is a significant correlation between PD-L1 positive expression and DSS(HR=1.54,95% CI=1.19～2.00,P=0.001).4.21 studies compared the expression of PD-L1 in patients of different genders.The positive rate of women(50.06%)was higher than that of men(41.55%),and the difference was statistically significant(RR=0.80,95%CI=0.68～0.94,P=0.005).5.6 studies compared the difference of PD-L1 expression in OSCC patients with different smoking status.The PD-L1 overexpression in non-smoking patients was significantly higher than that in smokers(OR=0.57,95% CI=0.41～0.78,P=0.0005).6.5 studies evaluated the overexpression of PD-L1 between drinkers and non drinkers in 956 patients,and the results showed that the positive expression rate of PD-L1 in non drinkers was significantly higher than that in drinkers(OR=0.29,95% CI=0.10-0.87,P=0.03).7.The positive rate of PD-L1 expression in patients with low/medium differentiation(51.9%)was higher than that in patients with good differentiation(49.3%),with a statistically significant difference between groups(HR=1.14,95% CI=1.02-1.28,P=0.02).8.The expression of PD-L1 in patients with OSCC at different T stages was compared in 18 studies.Among 941 patients at T3 to T4 stages,455 patients were positive for PD-L1 expression.The positive rate in patients with stage T3 to T4(48.3%)was significantly higher than that in patients with stage T1 to T2(45.9%)(HR=0.92,95% CI=0.85-0.99,P=0.03).9.17 Comparative studies of lymph node metastasis and PD-L1 expression showed that the positive expression of PD-L1 was significantly correlated with lymph node metastasis(HR=0.82,95%CI=0.75 ～ 0.89,P<0.00001).10.5 studies analyzed the relationship between distal metastasis and PD-L1 expression.The results showed that PD-L1 positive expression was significantly correlated with distal metastasis(HR=0.59,95% CI=0.48～0.71,P<0.00001).11.Thirteen studies explored the relationship between TNM stage and PD-L1 expression,and the results showed that PD-L1 positive expression was significantly correlated with TNM stage(HR=0.84,95%CI=0.77～0.92,P<0.0002).12.6 studies compared the relationship between tumor recurrence and PD-L1 expression.The results showed that the positive rate of patients with recurrence(48.7%)was lower than that of patients without recurrence(53.7%),but the difference was not statistically significant(HR=0.93,95% CI=0.76～1.12,P= 0.43).13.8 studies explored the relationship between HPV infection and PD-L1 expression.The results showed that PD-L1 positive was significantly correlated with HPV infection(HR=1.31,95% CI=1.01～1.69,P=0.04).Conclusion:1.PD-L1 expression status is significantly associated with certain clinicopathological characteristics of OSCC,including gender,smoking,alcohol consumption,degree of tissue differentiation,T-stage,lymphatic metastasis,distal metastasis,TNM stage,and HPV infection.2.The expression of PD-L1 in T3-T4 phase is significantly higher than that in T1-T2 phase,and it is highly expressed in patients with lymph node metastasis,distal metastasis,and recurrence,suggesting that abnormal expression of PD-L1 is a risk factor for the occurrence and development of OSCC.3.In patients with OSCC with high expression of PD-L1,DSS is significantly lower than in patients with low expression of PD-L1,suggesting that PD-L1 may be a predictive marker of poor prognosis in OSCC.