In this context, a pattern of strong Shh expression has been identified in reactive alveolar epithelial cells as well as in epithelial cells lining the honeycomb cysts in IPF lungs [47,48], while microarrays indicated up-regulation of its primary receptor (Table 1), suggesting that the Shh pathway is activated on in this disease. The gene discussed is SHH; the disease is idiopathic pulmonary fibrosis.