Importantly, these functional and mechanistic effects have been shown to be accompanied by clinically relevant implications, as the overexpression of HOTAIR is linked to a dismal prognosis in patients diagnosed with numerous types of cancer (e.g., breast cancer [49], esophageal squamous cell carcinoma [50,51], colorectal cancer [22], glioblastoma [14], and others) [15]. This evidence concerns the gene HOTAIR and breast cancer.