At the single-cell level, the EpC cluster exhibited the highest module score for the lipid oxidation gene signature (Fig. 3c and the gene list is presented in Supplementary Table 2), which includes ALOX15, SLC27A2, ALOX5 and PLA2G7, genes that are significantly upregulated in CRSwNP compared with healthy controls (Fig. 3d). Here, ALOX15 is linked to chronic rhinosinusitis with nasal polyps.