HOTAIR and breast cancer: Moreover, breast cancer belongs to the most intensively studied malignances in respect to their regulation by lncRNAs, and HOX (homeobox) transcript antisense RNA (HOTAIR) is an lncRNA, which may play an important role in this regulation, mainly due to a wide spectrum of miRNAs interacting with HOTAIR and its effect on matrix metalloproteinases (MMPs) [26,27,28,29].