Steroids, which are well known for their effect on suppressing inflammation and widely used for relieving lung inflammation in respiratory diseases, such as asthma35 and chronic obstructive pulmonary disease (COPD)36, may also exert their effect through upregulation of CFTR since a number of hormones, such as estrogen37 and glucocorticoid38, have been shown to have effect on CFTR expression. Here, CFTR is linked to chronic obstructive pulmonary disease.