Table I. Primary human breast epithelial cells (HBEC) treated with 17 β-estradiol (E2) plated on collagen.

Primary cells were plated in collagen after treatment with E2. As control, the cells were treated with DMSO (vehicle in which E2 was dissolved). The means of spherical masses (±SD) in 4 wells are indicated.

Primary cells designation	Treatment	Number of spherical masses on collagen
HSM3 left	DMSO	0
	70 nM E2	2.75±0.5
308 Left	DMSO	0
	70 nM E2	15.5±1.7
307 left	DMSO	0
	70 nM E2	4.25±1.2