Mapping Normal Breast Development for Clues.

• Position: BREAST CANCER

Breast cancer is one of the most-prevalent cancers, and some forms rank among the most difficult to treat. Its various types and involvement of many different cells make targeting such tumors difficult. Now, researchers at the Salk Institute for Biological Sciences, La Jolla, Calif., have used a state-of-the-art technology to profile each cell during normal breast development.

"In order to understand what goes wrong in breast cancer, we need to first understand how normal development works," says Geoffrey Wahl, professor in the Gene Expression Laboratory. "This study represents a major step in that direction, as we were able to profile each cell during breast development. We expect this information to be a valuable hypothesis-generating resource for the mammary gland community."

Mature breast tissue contains two main cell types, which often are involved in breast cancers: luminal and basal. Luminals line the ducts and produce milk...