Second, and similarly to asthma, COPD patients display goblet cell hyperplasia (in large airways) and metaplasia (in small airways, where virtually no goblet cells are found in healthy subjects) (Kim et al., 2008; Gohy et al., 2019), a feature that is driven by the transcription factors SPDEF and FOXA3 (Park et al., 2007; Chen et al., 2014). Here, SPDEF is linked to asthma.