A linear correlation analysis was carried out between these parameters, which revealed that follistatin protein levels were positively correlated with activin A protein levels in CRSsNP (r = 0.819, p = 0.001) and in CRSwNP (r = 0.532, p = 0.013) (Fig 1). The gene discussed is FST; the disease is chronic rhinosinusitis with nasal polyps.