Objective        To determine the breast cancer stem-like traits of drug surviving cells (DSCs) and the effect on the formation of transplanted tumor in nude mice for the DSCs’ biological features.          Methods        Breast cancer cell line MCF-7 was weekly treated with docetaxel (DTX) at the concentrat

ion of 0.5 μg/mL

and the cells at the 1st to 4th generation of DSCs were individually named as DSCs 1 to 4. The untreated MCF-7 cells served as blank control cells. The cell cycle distribution of MCF-7 and DSCs 1 to 4 were tested by flow cytometry. MCF-7 cells and DSCs 1 to 4 were cultured in serum-free suspension culture medium to acquire microspheres of breast cancer stem cells (BCSCs). The expression of BCSCs marker ALDH1

CD44

CD24 and ABCG2 at mRNA and protein levels were detected by real-time q-PCR and Western blotting. Nude mice transplantation tumor was prepared to evaluate the time

rate and volume of tumor formation of MCF-7 cells and DSCs 1 to 4

respectively.          Results        The cell population of stationary phase (G

0

/G

1

) was significantly increased in DTX treated groups DSCs 2 to 4 compared with MCF-7 cells. Moreover

DSCs  2 to 4 had stronger ability of forming microspheres of BCSCs than MCF-7 cells. The results of real-time qPCR and Western blotting showed that the expression of BCSCs markers ALDH1

CD44

+

/CD24

-

and ABCG2 was obviously up-regulated in DSCs 2 to 4 (P0.05). Furthermore

the growth rate

the volumes of tumors were significant elevated in DSCs 2 to 4 compared with MCF-7 cells (P0.05). Whereas

DSCs 1 had no significant difference in above indexes compared with blank control MCF-7 cells.         Conclusion        DSCs exhibit the features of BCSCs after being treated with DTX

and promote the formation of xenograft tumor in nude mice.