RUNX3 and bronchopulmonary dysplasia: Compared with the control group, RUNX3 sequence 1 (−5407 ~ −5142 bp) and sequence 2 (−5407 ~ −5215 bp) both significantly bound to H3K27me3 or EZH2 at high levels in the BPD model group at 14 days (Fig. 8a, b; P < 0.05); binding between RUNX3 sequence 2 and H3K27me3 was more significant (P < 0.05).