MUC4 and chronic rhinosinusitis with nasal polyps: Previous studies have shown that increased expressions of pro-inflammatory cytokines, such as interleukin-1β, intercellular adhesion molecule 1, nuclear factor-κB, glucocorticoid receptor-β, transforming growth factor-β1 and mucin 4, in nasal polyp tissues were associated with a poor response to GC treatment, suggesting these pro-inflammatory cytokines might be involved in pathogenesis of GC resistance and could potentially be as biomarkers of GC insensitivity in CRSwNP patients [11, 19, 20].