The different kinds of cells that make up a breast arise from a small number of breast stem cells, whose immediate descendants are the progenitors that give rise to various normal breast cells. Now a group of researchers led by Baylor College of Medicine has shown that these progenitor cells can also be induced to form breast tumors of a unique type, as reported online in the journal Oncogene.

Unique mouse model

The group has devised a way to target a cancer-causing gene to different types of normal cells in a mouse breast, and discovered that when one such gene is inserted only in the progenitor cells, tumors arise that closely resemble a type of human breast cancer for which no mouse model existed before.

"This is the first model of this kind of tumor," said Dr. Yi Li, assistant professor in the Lester and Sue Smith Breast Center at BCM. "This mouse model will help us discover how this kind of tumor forms, and how best to attack it."

"From a scientific point of view, these findings tell us that the cell of origin affects what kind of cancer you get," Li added, "because the same cancer-causing gene targeted to other breast cells causes different tumors."

Targeting other breast cancer genes

Li is also trying to learn whether this group of cells always morph into this form of cancer. "In this case, we targeted a particular cancer-causing oncogene to a select subset of cells," he said. "Our next step is to target other breast cancer genes into the same progenitor cells and see if we can induce them to become other types of breast cancer."

Others who took part in this research include Dr. Wen Bu, Gladys D. Morrison, Dr. Shixia Huang, Dr. Chad J. Creighton, Dr. Jian Huang, Dr. Gary C. Chamness, and Dr. Susan G. Hilsenbeck, all of BCM, Dr. Jiang Chen and Dr. Dennis R. Roop of the University of Colorado, and Dr. Andrew D. Leavitt of the University of California San Francisco.

Funding for this work came from the United States Army, the National Institutes of Health, the Mouse Models of Health Consortium, and the National Cancer Institute.