ABSTRACT
<p><b>OBJECTIVE</b>To isolate breast cancer stem cells from breast cancer patients and identify their biological characteristics.</p><p><b>METHODS</b>Mammospheric cells were purified and enriched from the tumor tissues of breast cancer patients using mammosphere culture. Their expressions of CD44 and CD24 were analyzed by flow cytometry, and ALDH1, ESA and Oct4 expressions were determined by Western Blotting. The primary mammospheric and adherent cells, at the density of 2×10(4), 2×10(5) or 2×10(6), were inoculated into NOD/SCID mice to observe their tumorigenic and metastatic activities.</p><p><b>RESULTS</b>With mammosphere culture method, 62.36% of the mammospheric cells showed CD44(+)/CD24(-/low) phenotype. The expressions of ALDH1, ESA and Oct4 in the mammospheric cells were significantly higher than those in the adherent culture-derived breast cancer cells (P<0.05). Primary mammospheric cells were at least 100-fold more tumorigenic than the adherent cells; the mammospheric cells were associated with liver or lung metastases, but the adherent cells were not.</p><p><b>CONCLUSION</b>Mammosphere culture can be employed to obtain breast cancer stem cells from the tumor tissues of breast cancer patients.</p>