High Frequency of Programmed Death-ligand 1 Expression in Emphysematous Bullae-associated Lung Adenocarcinomas

Our objective is to clarify the prevalence of programmed death-ligand-1 (PD-L1) expression in emphysematous bullae (EB)-associated lung adenocarcinomas. Seventy patients (19.0%) were positive for PD-L1 expression. Thirty-six (44.4%) and 29 (58.0%) of 81 and 50 patients with EB and cancer adjoining EB, respectively, were positive for PD-L1 expression. EB-associated lung adenocarcinomas express PD-L1 protein more frequently than those without EB. Objective Emphysematous bullae (EB) are known to be associated with a high incidence of lung cancer; however, the reason for this has yet to be elucidated. The objective of the present study was to clarify the prevalence of programmed death-ligand-1 (PD-L1) expression in EB-associated lung adenocarcinomas. Patients and Methods A total of 369 patients with resected lung adenocarcinoma whose preoperative computed tomography findings were available for the examination of EB were analyzed for PD-L1 expression by immunohistochemistry and evaluated to determine the association between PD-L1 expression and EB-related adenocarcinomas. Results Among 369 patients, EB and cancer adjoining EB (Ca-ADJ) were identified in 81 (22.0%) and 50 (13.6%) patients, respectively. EB and Ca-ADJ were significantly associated with male gender, a smoking habit, a decreased forced expiratory volume in 1 second, a relatively higher tumor grade, advanced T status and stage, the presence of pleural and vessel invasion, invasive pathologic subtypes, and wild-type epidermal growth factor receptor. Seventy patients (19.0%) were positive for PD-L1 expression, whereas the remaining 299 patients (81.0%) were negative. Thirty-six (44.4%) and 29 (58.0%) of 81 and 50 patients with EB and Ca-ADJ, respectively, were positive for PD-L1 expression, which was shown to be significant by the Fisher exact test (P < .001 and P < .001, respectively). Among the 81 lung adenocarcinomas with EB, Ca-ADJ was significantly associated with PD-L1 expression (P = .021). In a multivariate analysis, the presence of Ca-ADJ was found to be an independent predictor of PD-L1 expression. Conclusions EB-associated lung adenocarcinomas express PD-L1 protein more frequently than those without EB.