3D Primary Culture Model to Study Human Mammary Development

We present a protocol for expanding human mammary tissues from primary patient-derived cells in three-dimensional (3D) cultures. The primary epithelial cells are seeded into 3D hydrogels with defined components, which include both proteins and carbohydrates present in mammary tissue. Over a span of 10-14 days, the seeded cells form mammary tissues with complex ductal-lobular topologies and include luminal and basal cells in the correct orientation, together with cells that stain positively for stem cell markers. In addition to recapitulating key architectural features of human mammary tissue, the expanded tissues also respond to lactogenic hormones including estrogen, progesterone, and prolactin. We anticipate that these cultures will prove useful for studies of mammary development and breast cancer.