Fig. 1: iFRET quantifies PD-1/PD-L1 interaction state with patient outcome in malignant melanoma and NSCLC.
From: Quantification of biomarker functionality predicts patient outcomes
a iFRET, a two-site assay simultaneously labels PD-1 and PD-L1 in patient samples. This allows the detection and quantification of PD-1 and PD-L1 interaction, alongside receptor and ligand expression. The black and white intensity maps show PD-1 and PD-L1 expression in an FFPE NSCLC sample. The pseudocolour lifetime map indicates FRET occurring between the labelled PD-1 receptor and PD-L1 ligand. This is correlated to a FRET efficiency of 20.77% and a receptor–ligand distance of 7.29 nm. b iFRET correlates PD-1/PD-L1 interaction state with overall survival in malignant melanoma. (Top) Kaplan–Meier curve indicates that patients with a higher PD-1/PD-L1 interaction have a significantly worsened overall survival (p = 0.05, χ2 = 3.914). (Bottom) Kaplan–Meier curve correlates overall survival with PD-L1 expression. Here, PD-L1 expression does not correlate with patient outcome (p = 0.87, χ2 = 0.027). Modified from Sanchez-Magraner et al.5.
