SHH and chronic obstructive pulmonary disease: Genes that are hypermethylated and downregulated in COPD, including genes related to lung function, such as EP300, EPAS1, FOXF1, FOXA2, KDR, LAMA5, SHH, NKX2-1, VEGFA, FZD1, NUMB, and PKDCC[34]–[37], are enriched for GO biological processes (S6 Table) such as regulation of cell communication (p-value = 1.98×10−8), regulation of multicellular organismal development (p-value = 2.13×10−7), and tissue morphogenesis (p-value = 4.43×10−7).