"Virtual" breast useful as cancer assay.

Virtual" breast useful as cancer assay

By taking advantage of a cell-culture technique to make breast cells grow more naturally outside the body, researchers have developed a new way to distinguish normal cells from tumor cells. Over the past decade, Mina Bissell and her colleagues at Lawrence Berkeley Laboratory in Berkeley, Calif., have learned that adding cellular scaffolding called a basement membrane to breast cells growing in a laboratory dish causes those cells to behave as if they were still in the body. Instead of growing into a flat layer, the cells form three-dimensional structures (above), and even secrete milk proteins. Working with European collaborators, Bissell has now discovered that within a week, normal breast cells also form new basement membranes, while tumor cells do not. This difference provides the fastest assay yet for telling the two kinds of cells apart, she reports. Also, adding the metastasis suppressor gene nm23 to tumor cells enables them to make this scaffolding, she says.