Researchers at the University of California, Berkeley, and the Lawrence Berkeley National Laboratory have put the squeeze -- literally -- on malignant mammary cells to guide them back into a normal growth pattern. The findings, presented today (Monday, Dec. 17) at the annual meeting of the American Society for Cell Biology in San Francisco, show for the first time that mechanical forces alone can revert and stop the out-of-control growth of cancer cells. This change happens even though the genetic mutations responsible for malignancy remain, setting up a nature-versus-nurture battle in determining a cell’s fate.