PCDH1 and asthma: Noteworthy, we showed that expression levels of PCDH1 mRNA and protein isoforms increased during differentiation of primary bronchial epithelial cells (PBECs) cultured under air-liquid interface (ALI) conditions [6], indicating that PCDH1 might contribute to bronchial epithelial cell differentiation or establishment of the epithelial barrier, a process that is impaired in asthma [7].