# Evaluating Transcriptomic Biomarkers for rHuEPO Detection: Assessing the Impact of Exercise and Altitude Exposure

## TL;DR

This study identifies 50 genes that reliably detect rHuEPO use, even after accounting for effects from exercise and altitude.

## Contribution

A refined gene panel of 50 rHuEPO-specific biomarkers unaffected by physiological stressors like exercise or altitude.

## Key findings

- 94 of 153 rHuEPO-responsive genes overlapped with altitude exposure.
- 34 of 153 genes overlapped with exercise responses.
- 50 genes remained unaffected by either exercise or altitude and are enriched in post-translational regulation and transport pathways.

## Abstract

Recombinant human erythropoietin (rHuEPO) is often misused in endurance sports due to its potent erythropoietic effects. While transcriptomic biomarkers hold promise for detecting rHuEPO use beyond conventional testing windows, many proposed gene markers may also respond to physiological stimuli such as exercise or altitude. This study compared 153 previously reported rHuEPO‐responsive genes in whole blood with transcripts identified during exercise (GEPREP database) and high‐altitude exposure (four independent studies). For the exercise dataset, gene‐level statistical outputs were obtained directly from the GEPREP database, while biological relevance was calculated using Cohen's d. Analyses of altitude and rHuEPO datasets followed the original statistical procedures described in each study. Among the 153 rHuEPO‐responsive genes, 94 overlapped with altitude and 34 with exercise. However, 50 genes remained unaffected by either exercise or altitude stimuli. Enriched in post‐translational regulation and intracellular transport pathways, these genes represent promising candidate transcriptomic markers of rHuEPO administration. This work provides a refined gene panel that reduces the likelihood of false positives and requires further experimental validation before integration into RNA‐based detection tests.

A two‐stage transcriptomic filter comparing rHuEPO, exercise and altitude responses reduced 153 candidate genes to 50 that were unaffected by physiological stimuli. These retained transcripts offer focused biomarker leads to strengthen antidoping detection of rHuEPO.