Correlation and prognostic significance of PD-L1 and P53 expression in resected primary pulmonary lymphoepithelioma-like carcinoma.

Background: Aberrant expression of programmed cell death-ligand 1 (PD-L1) and protein 53 (P53) has been observed in various malignancies, and recently, the mechanism of PD-L1 regulation by P53 has been elucidated. We aimed to explore possible correlations between PD-L1 and P53 expression and the prognosis of patients with resected pulmonary lymphoepithelioma-like carcinoma (LELC).

Methods: A total of 67 consecutive patients with primary pulmonary LELC who underwent radical resection from January 2003 to December 2014 were enrolled in our study. Membranous PD-L1 and nuclear P53 expression were detected by immunohistochemical staining (IHC).

Results: Positive expression of PD-L1 in tumor cells (TCs), PD-L1 in tumor-infiltrating lymphocytes (TILs) and P53 was investigated in 44 patients (65.7%), 37 patients (55.2%), and 34 patients (50.7%), respectively. Using univariate and multivariable analysis, both PD-L1 (+) in TCs and P53 (+) were observed to be significantly independent prognostic factors associated with longer disease-free survival (DFS, P=0.037 and 0.039, respectively), along with early stage LELC (P=0.037), but had no association with overall survival (OS) (P>0.05). In the P53 (+) group, the rate of patients with PD-L1 (+) in TCs was significantly higher than in the P53 (-) group (85.3% 45.5%, P=0.001). In addition, among the 45 patients who underwent adjuvant chemotherapy, DFS was significantly longer in patients with either PD-L1 (+) in TCs or P53 (+) (P=0.036 and 0.044, respectively).

Conclusions: PD-L1 and P53 may be potential therapeutic targets for primary pulmonary LELC. PD-L1 (+) in TCs and P53 (+) were reliable predictors for longer DFS and benefits from adjuvant therapy in resected cases. Routine detection of these two indices in lung LELC may be warranted.