RESUMO
PURPOSE: Few cells with stem cell characteristics possess capabilities of self-renewal and differentiation, which leads to high tumorigenesis and resistance to standard chemotherapeutic agents. These cells are mostly quiescent, and arrest occurs at the mitotic G0/G1 phase in mitosis. We explored the effects of basic fibroblast growth factor (bFGF) on the MCF-7 cell cycle with CD44+/CD24-. METHODS: Cancer-initiating cells were propagated as mammospheres. The CD44+/CD24- subpopulation was sorted by a fluorescence activating cell sorter-Vantage flow cytometer. A cell cycle analysis was performed with different bFGF concentrations. RESULTS: Differences in the CD44+/CD24- cell proliferation under different bFGF concentrations were observed (p=0.001). When the bFGF concentration was increased, the proportion of CD44+/CD24- at G0/G1 decreased (p=0.023). CONCLUSION: We conclude that bFGF may sustain CD44+/CD24- cell proliferation and could promote cell progression through the G0/G1-->G2/S phase transition.