Mara Steinkamp, Graduate Student, Human Genetics and Diane Robins, Ph.D., Professor, Department of Human Genetics, University of Michigan Medical School

The mouse mammary gland consists of milk-producing alveolar cells and a network of ducts that transport the milk to the nipple. Beginning at puberty, ducts grow out from the nipple, invading the surrounding fat pad. Many of the factors important in the development of the mammary gland may also be involved in breast cancer initiation and in subsequent tumor growth. This picture shows the mature duct tree of a non-pregnant mouse. Ducts are visualized with a dye that can differentiate the ducts (brown/red), from the surrounding fat pad (yellow).