S100A9 and cystic fibrosis: For example, Clarke and colleagues performed a microarray study of primary epithelial cells from ΔF508 homozygotes and non-CF controls, which yielded a molecular signature of native CF airway epithelial cells in which a noteworthy number of genes involved in inflammation and defense were upregulated, including S100A8, S100A9, and SERPINA3 [20].