Table 1. Tumor incidence in limiting dilution assay.

Tumor incidence/injection
Cells Injected	1,000	100	10	Estimated cancer stem cell frequency with confidence intervals (95%)
4T1-DMSO	10/10	10/10	7/10	1 in 9 (4-18)
4T1-Benztropine mesylate	8/10	7/10	5/10	1 in 218 (100-479)***

4T1-luc2 spheres pretreated with benztropine mesylate or DMSO were dissociated into single-cell suspensions and injected into the mammary fat pads of mice in limiting dilution (10; 100; 1,000). Tumor formation was observed for four weeks following inoculation. BCSC frequency was calculated using ELDA.