HOTAIR and pachyonychia congenita: HOTAIR-mediated suppression of genes in PC is partly EZH2-dependent [10, 19], and HOTAIR knockdown affects genes involved in cell cycle progression and proliferation, including growth/differentiation factor 15 (GDF15), which inhibits cell growth and activates apoptosis [56, 57] and is co-regulated by HOTAIR and EZH2 [19].