HOTAIR and chondrosarcoma: The lncRNA HOTAIR is well characterized for recruiting the epigenetic modification factors, such as polycomb repressive complex 2 (PRC2), to regulate gene expression, thereby promoting tumor cell proliferation and migration.11, 107 Analogously, HOTAIR is upregulated in chondrosarcoma and induces DNA methylation of miR-454-3p promoter regions by recruiting EZH2 and DNA methyltransferase 1 (DNMT1), which markedly silences miR-454-3p expression.