HOTAIR and breast cancer: Firstly, the expression pattern of HOTAIR was explored in BC tissues and cells. QRT-PCR assay revealed that HOTAIR level was strikingly upregulated in 35 cases of BC tissues compared with adjacent normal tissues (Fig. 1a). The correlation between HOTAIR expression and the clinicopathological characteristics of BC patients showed that high HOTAIR expression was positively correlated with the TNM stage and lymph node metastasis of BC patients (P < 0.05, Table 1).