To examine the effect of PNA3 on ovarian and breast cancer cell lines overexpressing HOTAIR (Supplementary Fig. S1F, Supplementary Table S3), cells were treated with PNA3 or control PNA (1μM each) alone or in combination with chemotherapeutics cisplatin (CDDP) or etopiside, functional assays were performed (clonogenic survival, caspase 3/7 cleavage, and proliferation assays), and levels of EZH2 and histone H3 lysine K27 trimethylation (H3K27me3) were examined. This evidence concerns the gene EZH2 and breast cancer.