Positive expression of programmed death ligand-1 correlates with superior outcomes and might be a therapeutic target in primary pulmonary lymphoepithelioma-like carcinoma

BACKGROUND Primary pulmonary lymphoepithelioma-like carcinoma (LELC) is a rare subtype of non-small cell lung cancer (NSCLC), and no effective treatments have been defined for advanced disease. Programmed cell death-ligand 1 (PD-L1) is expressed in a group of cancers that may be suitable targets for specific immunotherapy. METHODS This study investigated the expression and clinical value of PD-L1 in pulmonary LELC. Seventy-nine patients with pulmonary LELC were investigated. Paraffin-embedded tumor sections were stained with PD-L1 antibody. Correlations of PD-L1 expression with clinicopathologic parameters and outcomes were analyzed. RESULTS Fifty patients (63.3%) were PD-L1 positive. The 3-year and 5-year progression-free survival (PFS) rate was 76.0% and 68.0%, respectively, and the 3-year and 5-year overall survival (OS) rate was 88.0% and 79.0%, respectively. Kaplan-Meier analysis revealed that patients with positive PD-L1 expression had longer PFS and OS than those with negative PD-L1 expression (P=0.019 and P=0.042, respectively). In a multivariate Cox regression model including age, tumor size, stage, and PD-L1 expression status, the latter three factors were found to be independent predictors of PFS (P=0.023, P=0.000, and P=0.009, respectively), but only stage was found to be an independent factor for OS (P=0.007), and PD-L1 expression status showed a trend to be independently correlated with OS (P=0.080). CONCLUSION Our results showed that a large proportion of patients with pulmonary LELC had positive expression of PD-L1, supporting the potential use of anti-PD-1/PD-L1-targeted therapies in this distinct type of NSCLC.