Abstract: Objective To investigate the differentiation and tumor-forming aitivity of oral squamous cell carcinoma stem cells. Methods The CD133⁺ and CD44⁺ cells were isolated by immunomagnetic beads from oral squamous carcinoma cells，and the purity of sorted cells and cell cycle were identified by flow cytometry.The CD133⁺ cell growth curve was determined. The selected cells were induced to differentiate into osteoblasts and adipocytes.In vivo tumorigenesis experiments were carried out using primary squamous cells and CD44⁺，CD133⁺ cells. Results The purity of CD44⁺ cells and CD133⁺ cells that were isolated by immuno-magnetic beads were more than 94% detected by flow cytometry. Most of their cell cycle were in G0/G1 phase.CD133⁺ cells entered log phase on the 2nd day after inoculation，and the cell doubling time was 3.22 d.After induction，CD44⁺ and CD133⁺ cells were successfully differentiated into osteoblasts and adipocytes. On the 3rd day after subcutaneous injection，new tumors could be touched， the tumor volume in the CD133⁺ cell group was the greatest in three cells，and HE staining showed that it was consistent with the pathological manifestations of oral squamous cell carcinoma. Conclusion High-purity oral squamous cell carcinoma stem cells can be successfully sorted by immunomagnetic beads method.CD44⁺ and CD133⁺ cells have great multidirectional differentiation，but the tumorigenicity of CD133⁺ is greater.

Key words: Oral squamous cell carcinoma, Magnetic bead sorting, Stem cells, CD44, CD133, Differentiation