Background: High Programmed death ligand 1 (PD-L1) expression are thought to be necessary to PD-1/PD-L1 axis blockades in many tumors. The aim of the study was to explore the variation of PD-L1 expression after neoadjuvant chemotherapy (NAC) in cervical squamous cell carcinoma (SCC) and its clinical implications.
Methods: A total of 142 paired SCC specimens before and after platinum-based NAC were obtained from cervical cancer patients. The expression of PD-L1 and CD3+, CD4+, CD8+ tumor infiltrating lymphocytes (TILs) was detected by immunohistochemistry and the association between TILs, chemotherapy response, clinical outcome and PD-L1 expression was evaluated.
Results: The fraction of patients with high PD-L1 expression was significantly increased from 32.4 to 46.5% after NAC (χ2 = 5.897, p = 0.015), while the increase of CD3+, CD4+, CD8+ TILs was not significant. High PD-L1 expression was not associated with CD3+, CD4+, CD8+ TILs before NAC, however CD8+ TILs infiltration was positively associated with high PD-L1 expression after NAC (r = 0.205, p = 0.014). The decreased PD-L1 expression was more observed in patients with clinical response to NAC (χ2 = 6.890, p = 0.009). A longer DFS was seen in patients with decreased PD-L1 expression than those with elevated or stable PD-L1 expression (p = 0.048, 95% CI: 0.091-0.987), while the difference was not significant in multivariate analysis (p = 0.113, 95% CI: 0.108-1.266).
Conclusions: Cisplatin based chemotherapy can increase PD-L1 expression in cervical cancer. The increased PD-L1 expression and a lymphocyte predominant microenvironment after chemotherapy provide a rational for use of PD-1/PD-L1 axis-inhibitor in the neoadjuvant setting.
Keywords: Cervix; Neoadjuvant chemotherapy; PD-L1; Squamous cell carcinoma; Tumor infiltrating lymphocytes.