Date Time Researchers Uncover How MN1 Overexpression Causes AML Meningioma-1 (MN1) is a protein whose overexpression has been linked to acute myeloid leukemia (AML) and brain tumors, and 70% to 80% of AML patients with high overexpression of MN1 die within two years. Yet the mechanism by which MN1 causes these diseases has largely remained a mystery. “Looking at the sequence, the protein has no obvious structure,” said Kathrin M. Bernt, MD, a pediatric oncologist in the Cancer Center’sLeukemia and Lymphoma Program at Children’s Hospital of Philadelphia (CHOP). “MN1 doesn’t resemble other typical oncogenes – or any other proteins – so it’s difficult to ascertain its function.”