The Clinicopathological And Prognostic Value Of PD-L1 Expression In Colorectal Cancer: Meta-analysis

Objective: To analyze the prognostic value of programmed death factor ligand 1(PD-L1)in colorectal cancer,and to guide the treatment of colorectal cancer.Methods: Electronic databases,such as PubMed,Web of Science,Embase,Cochrane library,China national knowledge Internet(CNKI)and Wanfang Database were searched to identify studies evaluating the PD-L1 expression and overall survival(OS)and clinical pathological features in these patients.Afterwards,the relevant data were extracted to perform the meta-analysis.Results: A total of 9187 patients were included in 30 studies.The combined hazard ratio(HR)was 1.12(95%CI 0.97-1.29,P=0.12),indicating that high expression of PD-L1 was not significantly correlated with poor prognosis of colorectal cancer.As to clinicopathological features,the merged odds ratio(OR)exhibited that highly expressed PD-L1 was firmly related to poor tumor differentiation(OR=2.46,95% 1.46-4.15,P=0.442),microsatellite instability(OR=1.87,95%CI 1.10-3.16,P=0.02),and right colon(OR=0.47,95%CI 0.29-0.78,P=0.003).The expression of PD-L1 in tumor cell is not correlative with patients' lymphatic invasion,BRAF mutation or KRAS mutation.Conclusion: The expression of PD-L1 can't be utilized as an independent factor in judging the prognosis of colorectal cancer,and patients with right colon cancer,poor tumor differentiation or MSI are more likely to express PD-L1.This conclusion may lay a theoretical foundation for the application of PD-1/PD-L1 immunoassay point inhibitors but still needs verifying by sizeable well-designed cohort studies.