CFTR and chronic obstructive pulmonary disease: If future studies in humans can confirm the results from our murine studies demonstrating an inverse relationship between WT CFTR function and severity of obstructive airway disease, VX-770 and potentially other CFTR modulators that improve surface expression and/or function of WT CFTR Cl− channels [49] may provide therapeutic opportunities for COPD in a subgroup of individuals with low levels of endogenous CFTR activity produced by either genetic factors or environmental factors such as cigarette smoke [12].