Abstract: HOX transcript antisense RNA (HOTAIR) is the first long chain non-coding RNA to be found with transcription regulation effect. As antisense RNA, HOTAIR itself does not encode proteins, but it acts as a transcription regulatory factor by effecting on different chromosomes of HOX gene cluster, thus playing an important role in the genomic control and development of tumor. Studies have shown that HOTAIR is dysregulated in several human cancers, such breast cancer, colorectal cancer, liver cancer, pancreatic cancer, laryngeal cancer, etc. High expression of HOTAIR can inhibit the expression of tumor suppressor genes, which will promote the tumor recurrence and metastasis, however down-regulated expression of HOTAIR will reduce the invasive ability of tumor cell. Researches in recent years have confirmed that HOTAIR expression is abnormal in breast cancer tissues, cell lines and peripheral blood, which is helpful to illuminate the mechanism of breast cancer development and the mechanism of drug resistance. Clinical studies further show that the detection of HOTAIR expression level is not only helpful to improve the diagnostic capability of breast cancer, but also helpful to promote clinical condition evaluation, prognosis judgment, curative effect evaluation and dynamic monitoring of tumor recurrence. In addition, HOTAIR expression may be related to biological behavior of breast cancer in different hormone receptor types. Exploration studies also shown that antitumor drugs designed according to carcinogenesis of HOTAIR will be able to bring light to the treatment of some refractory breast cancer, such as tamoxifen resistant breast cancer. This paper will review the research progress in recent years.