Moreover, lncRNA silencing resulted in reduction of cell proliferation rate, observed only in estrogen-responsive, ERα-positive BC cell lines MCF-7, T-47D and ZR-75-1 but not in ERα-negative MDA-MB-231 (TNBC) and MCF-10A (mammary epithelial) cells (Fig. 3C, Supplementary Fig. S3A–E). This evidence concerns the gene ESR1 and breast cancer.