NGF and obstructive sleep apnea syndrome: In the same year, Hou and colleagues (2024) studied the influence of NGF on the migration and metastasis of human OSA patients, demonstrating that NGF expression was significantly higher than that of other growth factors, and that NGF and matrix metallopeptidase-2 (MMP-2) expression levels were significantly higher in bone tissue samples from OSA patients compared to those from normal bone, and strongly correlated with tumor stage.