Quantifying PD1 Saturation by PDL1 in Tumor Tissue Using a Novel RNA Aptamer-Based Assay

Suresh Veeramani; Chaobo Yin; Nanmeng Yu; Kristen Coleman; Brian J. Smith; George J. Weiner

doi:10.3390/ijms27125469

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Quantifying PD1 Saturation by PDL1 in Tumor Tissue Using a Novel RNA Aptamer-Based Assay

Journal article

Open access

Peer reviewed

Quantifying PD1 Saturation by PDL1 in Tumor Tissue Using a Novel RNA Aptamer-Based Assay

Suresh Veeramani, Chaobo Yin, Nanmeng Yu, Kristen Coleman, Brian J. Smith and George J. Weiner

International journal of molecular sciences, Vol.27(12), 5469

06/17/2026

DOI: 10.3390/ijms27125469

PMID: 42353185

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Abstract

Therapeutic agents targeting the PD1–PDL1 interaction, commonly called PD1 blockade, are of great clinical value; however, predicting which patients will benefit has been inconsistent, in part, due to a lack of reliable biomarkers. Quantifying PD1 saturation by PDL1 in tumor tissue has the potential to serve as a biomarker; unfortunately, few diagnostic technologies are available to reliably quantify PD1 saturation in clinical biospecimens. Here, we report on a novel bioassay based on RNA aptamers, called the PD1 LIRECAP assay, that allows for quantification of the saturation of PD1 by PDL1 in formalin-fixed, paraffin-embedded (FFPE) tumor biospecimens. The assay is technically straightforward, high-throughput capable and reproducible. Results showed that quantification of PD1 saturation determined by PD1 LIRECAP assay correlates closely with PD1-mediated signaling and PD1–PDL1 proximity. Analysis of sarcoma FFPE biospecimens confirmed the assay to be consistent and revealed significant differences between patients as well as considerable intratumoral heterogeneity in PD1 saturation by PDL1. We conclude that this novel PD1 LIRECAP platform is technically feasible, reproducible and has the potential to be a superior predictive biomarker assay to predict the outcome of PD1/PDL1-based therapy. Similar assays based on this platform could be used in other systems and settings to quantify the interaction between two molecules.

PD1

PDL1

prognostic biomarker

ligand-receptor complexes

RNA aptamers

Details

Title: Subtitle: Quantifying PD1 Saturation by PDL1 in Tumor Tissue Using a Novel RNA Aptamer-Based Assay
Creators: Suresh Veeramani - University of Iowa
Chaobo Yin - University of Iowa
Nanmeng Yu - University of Iowa
Kristen Coleman - University of Iowa
Brian J. Smith
George J. Weiner - University of Iowa
Resource Type: Journal article
Publication Details: International journal of molecular sciences, Vol.27(12), 5469
DOI: 10.3390/ijms27125469
PMID: 42353185
NLM abbreviation: Int J Mol Sci
ISSN: 1661-6596
eISSN: 1422-0067
Publisher: Multidisciplinary Digital Publishing Institute (MDPI)
Grant note: Holden Comprehensive Cancer Center National Institutes of Health: P30 CA86862
The core resources used for this study are supported by National Institutes of Health grant P30 CA86862 (Holden Comprehensive Cancer Center).
Language: English
Date published: 06/17/2026
Academic Unit: Hematology, Oncology, and Blood & Marrow Transplantation; Pharmaceutical Sciences and Experimental Therapeutics; Biostatistics; Holden Comprehensive Cancer Center; Internal Medicine
Record Identifier: 9985176757402771

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