The ABCG2
+ subpopulation of human breast cancer cells (MCF7)was isolated using Anti‑ABCG2 (CD338) MicroBeads, an LS Column, and a QuadroMACS™ Separator. Cells were fluorescently stained with Labeling Check Reagent‑PE (# 130‑095‑228) and analyzed by flow cytometry using the MACSQuant
® Analyzer. Cell debris and dead cells were excluded from the analysis based on scatter signals and propidium iodide fluorescence.