Our study also revealed that not only can the overexpression of Sox9 in BPD reduce the overall expression level of β-catenin but also that the nucleocytoplasmic translocation of Sox9 can change the nucleocytoplasmic distribution of β-catenin by reducing its nuclear expression to inhibit the activation of the Wnt/β-catenin signaling pathway. The gene discussed is SOX9; the disease is bronchopulmonary dysplasia.