We aimed to compare intra- and extracranial responses to immune checkpoint inhibitors (ICIs) in lung cancer with brain metastases (BM), and to explore tumor microenvironments of the brain and lungs focusing on the programmed cell death-1 (PD-1)/programmed cell death ligand-1 (PD-L1) pathway.
The benefits of PD-(L)1 inhibitors in PD-L1(-) tumors are unclear, and no reports exist on the activity of these agents in brain metastases from SCCHN.
Overexpression of p53 and a higher PD-L1 protein H-score were detected in patients who underwent surgical treatment followed by chemotherapy as compared with those who underwent only surgical treatment The absence of brain metastases was associated with wild-type sequences of genes EGFR, CD267, CTLA-4, and ZEB1.
Anti-programmed death-1/programmed death ligand-1 agents represent a new valid therapeutic strategy for NSCLC as well as for several tumor types, but their efficacy on patients with BM is still unclear mainly due to the strict selection criteria adopted in clinical trials.
Immunohistochemical analysis confirmed the presence of CD8<sup>+</sup> T cells and low PD-L1 expression in the brain metastases before immunotherapy initiation.
However, little is known about the safety and feasibility of patients receiving anti-PD-1/PD-L1 therapy and stereotactic radiation for the treatment of brain metastases.
The aim of this study was to characterize the distribution of ICs and determine the expression of the checkpoint molecules programmed death protein 1 (PD-1) and its ligand, PD-L1, in brain metastasis of lung adenocarcinoma (LUAD) patients and to analyze their clinicopathological correlations.
When specimens were categorized using a proposed tumor microenvironment categorization scheme based on PD-L1 expression and TILs, there were significant changes in the classifications because many of the brain metastaseslacked either PD-L1 expression, tumor lymphocyte infiltration or both even when they were present in the primary lung cancer specimens (P = 0.009).