Abstract
The slow-cycling subpopulation plays an important role in anticancer drug resistance and tumor recurrence. Here, we describe a clinically relevant patient-derived xenograft model and a carboxyfluorescein succinimidyl ester dye that is diluted in a cell proliferation-dependent manner. We detail steps to separate active-cycling cancer cells and slow-cycling cancer cells (SCCs) in heterogeneous cancer populations to confirm their different cellular properties. This protocol can be used to distinguish SCCs, investigate their biology, and develop strategies for anticancer therapeutics. For complete details on the use and execution of this protocol, please refer to Cho et al. (2021).1.