Breast cancer-initiating cells have previously been shown to express aldehyde dehydrogenase (ALDH) intracellularly and CD44, but not CD24 at the cell surface.39–42 Hence, flow cytometry analysis was performed on TNBC cell lines MDA-MB 231, MDA-MB 468, and Hs 578t treated with OKN-007 for 48 hours and paclitaxel (100 μM) for the final 6 hours to determine the fraction of residual cells with a cancer-initiating cell phenotype (cells that express high levels of ALDH and CD44 but do not express CD24). Here, CD44 is linked to breast cancer.