Programmed Death-Ligand 1 and Vimentin: A Tandem Marker as Prognostic Factor in NSCLC

In non-metastatic non-small-cell lung cancer (NSCLC), outcomes remain poor. Adjuvant chemotherapies provide a limited improvement in disease-free survival. Recent exploratory studies on early-stage NSCLC show that immunotherapy given according to Programmed Death-Ligand 1 expression generates variable results, emphasizing a need to improve tumor characterization. We aimed to conjointly assess NSCLC, the expression of PD-L1, and epithelial-mesenchymal transition, frequently involved in tumor aggressiveness. 188 resected NSCLCs were analyzed. Among 188 patients with curatively resected NSCLC, 127 adenocarcinomas and 61 squamous cell carcinomas were stained for PD-L1 and vimentin expression. Overall survival has been compared regarding PD-L1 and vimentin statuses both separately and conjointly in Tumor Cancer Genome Atlas databases. PD-L1 and vimentin higher expressions were strongly associated (OR = 4.682, p < 0.0001). This co-expression occurred preferentially in tumors with lymph node invasion (p = 0.033). PD-L1 was significantly associated with high EMT features. NSCLC harboring both PD-L1^high/vimentin^high expressions were significantly associated with poor overall survival (p = 0.019). A higher co-expression of vimentin and PD-L1 was able to identify patients with worse outcomes. Similar to an important prognostic marker in NSCLC, this tandem marker needs to be further presented to anti-PD-L1 immunotherapies to improve outcome.