Through the UALCAN (http://ualcan.path.uab.edu/index.html, accessed on 12 March 2022) online tool to analyze the TCGA database, the results showed that HOTAIR was significantly overexpressed in luminal breast cancer, HER2-positive breast cancer, and triple-negative breast cancer (TNBC) (Figure 1B). Here, HOTAIR is linked to breast cancer.