FGF10 and chronic obstructive pulmonary disease: Interestingly, increased nuclear YAP levels, along with FGFR2B and WNT7b expression, were observed in squamous metaplastic areas within the airway epithelium of COPD subjects (Volckaert et al., 2017), suggesting that the Hippo pathway is inactivated to induce FGF10 expression and BSC amplification in human COPD.