Both cell counting and MTT assays revealed that with DIO3OS knockdown by LNAs (Supplementary Fig. 3m), the growth of BT549 cells was slightly impaired, while SKBR3 cells remained largely unaffected (Supplementary Fig. 3n, o), indicating a less important role of DIO3OS in these ER-negative or HER2-positive breast cancer. Here, ESR1 is linked to breast cancer.