In addition, we also identified many enriched signalling pathways associated with respiratory diseases, such as the apelin signalling pathway (Tatemoto et al., 1998; Yan et al., 2020), folate biosynthesis pathway (Stanisławska-Sachadyn et al., 2019), and arachidonic acid metabolism (Giudetti & Cagnazzo, 2012). Here, APLN is linked to respiratory system disorder.