Periostin is an established biomarker for asthma,20–22 its role in airway remodeling being exploited by an experimental asthma drug.23 The strong differential expression pattern between asthmatic and healthy subjects confirms its asthma association (Fig. 1a, fold-change FC = 1.2, p-value <3 × 10−6, Mann–Whitney U-test). The gene discussed is POSTN; the disease is asthma.