CD44 and neoplasm: Lastly, we performed flow‐sorting analyses to isolate HLA+/CD44+/Pan‐CK+ cell populations from blood and BM, and they were validated by further immunofluorescent staining of human HLA, CD44, Pan‐CK, and GCDFP‐15+ mammaglobin markers for the presence of human‐specific mammalian tumor stem cell phenotype (Fig. 2E).