Fig. 1: Enrichment of TNBC-CSC in hypoxia conditions.

a Hs578T and BT549 cells were exposed to 21 or 1% O2 for 24 h; CD44+/CD24− cells in both Hs578T and BT549 cell populations were detected by flow cytometry (*P < 0.05). b Representative images of mammospheres formed from Hs578T and BT549 cells in 1% O2 condition (scale bar, 100 µm). The quantification of mammosphere formation efficiencies (sphere number) and the mean sphere sizes was shown (**P < 0.01). c, d qRT-PCR (c) and western blotting (d) were employed to determine the expressions of the indicated CSC-associated genes in mammospheres of Hs578T and BT549 cells under hypoxia conditions (**P < 0.01).