CD44 and breast cancer: For example, γ-secretase inhibitor MK-0752 from Merck completed phase I/II clinical trials for metastatic BC, and patient biopsy samples showed a decrease in cell population with the CD44+/CD24− and ALDH+ phenotype, which was the first evidence of the benefits of the BCSC-targeted therapy through targeting the Notch signaling pathway in combination with docetaxel as the systemic cytotoxic therapy [72,208].