MORE: http://mednews.stanford.edu: "Tumor-suppressor proteins work to inhibit tumor growth in our bodies and when they win, they spare us a battle with cancer. But one such protein, menin, appears to have a split personality. Though menin is well-known for its ability to suppress endocrine tumors, researchers at Stanford University School of Medicine have discovered that it is also a key player in the development of some forms of acute leukemia."