High-depth capture-sequencing data showed that BC ERα-FL(−) cells expressing exclusively ERα-LBD, such as MDA-MB-453/-231 and PDX-ERα, have higher abundance of ESR1 read counts in the C-terminus (CDS exons #4, 5, 6, 7 and 8), compared to the N-terminus (CDS exons #1–3). This evidence concerns the gene ESR1 and breast cancer.