Usefulness of the nCounter Analysis System to Monitor Immune-related Biomarkers in PBMCs During Anti-PD-1 Therapy

BACKGROUND/AIM: Immune checkpoint inhibitors (ICIs) have dramatically changed the clinical outcomes of advanced tumours. However, biomarkers for monitoring immunological features during immunotherapy remain unclear, especially those in the peripheral blood, which are easily available. This study evaluated the usefulness of nCounter Analysis System in identifying immunological biomarkers in peripheral blood mononuclear cells (PBMCs) during ICI therapy. PATIENTS AND METHODS: PBMCs from two patients who responded well to ICI therapy were used, and the expression levels of immune-related mRNA and extracellular proteins were analyzed. RESULTS: Changes in the expression levels of 55 genes from pre-treatment to on-treatment were bioinformatically similar between the two cases. The expression levels of PD-1 were consistent with those by flow cytometry analysis, a reliable tool for monitoring various markers. CONCLUSION: The nCounter Analysis System may be a potent tool to simultaneously investigate genes and proteins on PBMCs as biomarkers during immunotherapy using a small amount of sample.