ABCG2

ABCG2-positive IGR39 cells expanded substantially more than ABCG2-negative cells. Model fits imply that ABCG2 strongly enriches for cancer stem cells but is not a pure marker. Only a minority of ABCG2-positive cells were inferred to be cancer stem cells. Both sorted populations expressed ABCG2 again after 139 days, consistent with reversible marker expression or imperfect specificity. Cells were sorted by ABCG2 expression using antibody staining and flow cytometry.