Our previous study proved that the 5′ domain, but not its 3′ domain, which was the function domain of HOTAIR is responsible for tumorigenesis and metastasis in glioblastoma and breast cancer, by recruiting and binding EZH2, the catalytic subunit of PRC2, to silence target genes nemo-like kinase (NLK) [12–14]. The gene discussed is HOTAIR; the disease is breast cancer.