In this study, immortalized mesenchymal stem cell lines can be formed in soft agar cloning, cloning rate was only 2.1%, but not tumorigenicity in nude mice.

• 本实验的永生化间充质干细胞系可在软琼脂内形成克隆，克隆形成率只有2.；1%25，但不在裸鼠体内致瘤。