However, other important molecules have been associated with phenotypes of asthma, including tumor necrosis factor- (TNF-) α. This proinflammatory cytokine has been found in increased concentrations in asthmatic airways and the inhalation of TNF-α has been shown to cause airway hyperresponsiveness and increased sputum neutrophil counts in healthy volunteers [4]. The gene discussed is TNF; the disease is asthma.