ESR1 and breast cancer: Furthermore, Nasr et al. have recently established a BC cell line from a ER+/PR+/HER2- tumor; the cell line consists of 92% ALDH1+ cells and 0.97–5.4% of CD44+CD24−/low cells, and OCT4, SOX2, and NANOG were overexpressed, suggesting the line being essentially cells with BCSC properties [140].