CD155 expression and co-expression with PD-L1 are not associated with poor prognosis in patients with stage II and III lung adenocarcinoma undergoing surgical resection

Background: CD155 has been identified as a ligand for T-cell immunoreceptor with Ig and ITIM domains. Herein, we investigated the relationship between the expressions of CD155 and programmed cell death-ligand 1 (PD-L1) and clinical outcomes in patients with surgically resected lung adenocarcinoma. Methods: This study included 426 patients diagnosed with pathological stage (pStage) I to III lung adenocarcinoma who underwent surgery at Kyushu University Hospital. The number of tumor cells expressing CD155 and PD-L1 was assessed by immunohistochemistry, and the clinical significance of CD155 expression and CD155/PD-L1 co-expression in prognosis was investigated. Results: Among the enrolled cohort, 320 (75.1%), 60 (14.1%), and 46 (10.8%) patients were diagnosed with pStage I, II, and III, respectively. Tissues from 112 patients (26.3%) were classified as having high CD155 expression. Co-expression of CD155 and PD-L1 was observed in 44 patients (10.3%). The High CD155 and CD155/PD-L1 co-expression groups had significantly poorer prognosis in pStage I to III lung adenocarcinoma. However, subgroup analysis revealed that the clinical significance of both CD155 expression and CD155/PD-L1 co-expression differed widely between patients with pStage I and II-III. Multivariate Cox proportional hazards regression analyses showed that high CD155 expression and CD155/PD-L1 co-expression were not independent poor prognostic factors in pStage II-III lung adenocarcinoma. Conclusion: Our findings suggest that neither CD155 expression or CD155/PD-L1 co-expression are associated with poor prognosis in pStage II-III lung adenocarcinoma.