BRCA1 and breast cancer: HOTAIR might act asa gene expression regulator in the BC related to mutationsof BRCA1. HOTAIR promoter contains several estrogenreceptors (ERs), and it has been shown that estradiolregulated HOTAIR expression in ER positive BC cells.However, this regulation was abolished in BC cells withinactive ERs, indicating the critical role of these receptorsin estradiol-mediated control of HOTAIR expression (20).HOTAIR and some other lncRNA expression analysesin 164 ER-positive primary BC cases demonstrated thatthese lncRNAs could be independent prognostic markers(21).