– RUNX3 is critical for lung development and BPD regulation. – Disruption in RUNX3 expression is linked to abnormal lung architecture and impaired alveolarization. – RUNX3 may serve as a prognostic marker and therapeutic target for BPD. – DNA methylation and H3K27me3 alterations affect RUNX3 in BPD models. – Increased DNMT1 and DNMT3b expression correlates with decreased RUNX3 levels in hyperoxia models. This evidence concerns the gene RUNX3 and bronchopulmonary dysplasia.