Prognostic impact of the tumor immune microenvironment in pulmonary pleomorphic carcinoma

Abstract

Introduction: Pulmonary pleomorphic carcinoma (PC) is a rare non-small cell lung carcinoma (NSCLC) and is characterized by sarcomatoid and NSCLC components. This study aimed to characterize the association between immune microenvironmental factors and clinicopathological characteristics of PC.

Methods: Eighty consecutive PC patients who had undergone complete surgical resection were enrolled. We calculated the immunohistochemical staining scores for E-cadherin, vimentin, programmed death ligand 1 (PD-L1), and carbonic anhydrase IX in cancer cells and counted the numbers of CD204-positive tumor-associated macrophages (TAMs) and Foxp3-, CD8-, and CD20-positive tumor-infiltrating lymphocytes (TILs). We also examined the association between these scores and the prognostic outcomes.

Results: The staining score for PD-L1 in cancer cells and the number of CD204-positive TAMs in the sarcomatoid component were significantly higher than those in the NSCLC component; E-cadherin score in the sarcomatoid component was significantly lower. Patients with high PD-L1 expression in the NSCLC component had significantly longer overall survival (OS) and recurrence-free survival (RFS) than those with low PD-L1 expression in the NSCLC component (OS: p = 0.001, RFS: p = 0.038). Multivariate analysis revealed that high PD-L1 expression in the NSCLC component was an independent favorable prognostic factor for OS (p = 0.018), whereas high PD-L1 expression in the sarcomatoid component was not. The number of CD8-positive TILs was significantly higher in the high PD-L1 expression group than in the low expression group (NSCLC components: p < 0.001).

Conclusion: High PD-L1 expression in the NSCLC component may be associated with a favorable prognostic value in pulmonary PC.

Keywords: Immune microenvironment; Non-small cell lung cancer; Programmed death ligand 1; Pulmonary pleomorphic carcinoma; Sarcomatoid.