First Steps

Watching for signals
(continued)

"Cells in an adult are tightly regulated and their growth tightly controlled," said Carraway. "Somehow, tumor cells turn on signals in the cell that short circuit this regulatory process. If we could understand how, we'd have better knowledge on which to develop new treatments for cancer patients.''

Defining the "somehow" is what drives his research.

Tyrosine kinases are enzymes that control cell growth and proliferation. They play a pivotal role in signal transduction, the process by which a cell responds to changes or signals in its environment. These signals tell the cell when to divide, grow and die.

Carraway's specialty is a growth factor receptor protein called Erb2 but known more commonly as HER-2. Thanks to a drug called Herceptin, lots of people have heard of this protein.

HER-2 sits on the surface of epithelial cells (cells that line tissue) and binds with growth factors. In a person with normal HER-2, this protein controls development of mammary, heart and other tissues.

"You need some HER-2 for normal functioning," said Carraway. "Mice bred to not have HER-2 die after 10 weeks of gestation because their heart muscles don't develop properly."