ESR1 and triple-negative breast carcinoma: Additionally, the CD44+/CD24− cell population derived from MCF-7 cells showed lower tumorigenicity capacity compared to the CD44+/CD24− population derived from triple-negative breast cancer cell line, suggesting that CD44+/CD24− and ALDH1+ are excellent markers of BCSCs from ER- tumors but possibly less suitable markers for BCSCs of ER+ tumors [62].