John Kersey, M.D.

MINNEAPOLIS / ST. PAUL (June 28, 2006) — Researchers at the Masonic Cancer Center have successfully produced the first mouse model with the gene of a rare and frequently fatal form of blood cancer that most often strikes children from infancy to one year of age.

An article and commentary about the breakthrough will be published in the July issue of Blood, the journal of the American Society of Hematology.

This achievement opens the doors for further investigating the biology, developing new treatments, and possibly finding a cure for infant acute lymphoblastic leukemia (ALL). Infant ALL currently affects about 200 babies born each year in the United States, and it claims as many as 60 percent of them before their first birthday.

John Kersey, M.D., a physician and researcher specializing in childhood cancers and director of the University's Cancer Center, led the laboratory research team that produced this first genetically-engineered mouse with the MLL-AF4 fusion gene that provides an experimental model of infant ALL. This abnormally formed gene is considered the predominant source of the disease.

"Now this mouse model will be used as the vehicle for further research and developing new treatments for this disease," Kersey said. "Hopefully, this mouse will help us find a cure so that in the not too distant future, a parent does not have to experience the agony of losing a baby to this cancer."

Leukemia originates in the bone marrow; it is a cancer that suppresses the growth of new red blood cells. Although the MLL-fusion gene is predominantly diagnosed in infants, adults also can get the disease and about two-thirds of them die on average within two years of diagnosis. Many adults develop this disease as a secondary cancer, having been previously treated with chemotherapy or radiation for another cancer, such as breast cancer.

Like all leukemias, infant ALL is an acquired, not inherited, genetic disease. DNA, which contains the code for a person's genetic structure, goes through a normal process of breaking and rejoining. During this replication process, researchers believe the genetic material in a few bone marrow cells gets damaged.

"Sometimes a mistake happens in the rejoining of the DNA and the result can be leukemia," Kersey said. "In about 75 percent of infants with infant ALL, the genetic rearrangement of the gene, MLL, occurs in the womb as the baby is developing. We believe the MLL and AF4 genes fuse by mistake and form the basis for infant ALL."

In an "Inside Blood Commentary" about the Masonic Cancer Center's achievement, Drs. Mel Greaves and Eric So, Institute of Cancer Research in London, England, wrote: "The report from the Kersey laboratory documents the long-awaited successful establishment of a murine (mouse) model for leukemogenesis by the MLL-AF4 fusion gene."

While researchers have long known that the MLL-AF4 fusion gene is the most common cause of infant ALL, the absence of a laboratory model to more intensely study this disease has frustrated researchers for nearly two decades, Greaves and So noted. Without an experimental model as developed by the Kersey team, exploring and designing curative treatments has been impossible.

The next step for Kersey and his colleagues is to accelerate their research on drugs that they think may provide better treatment for infant ALL than the current chemotherapy regimens.

Kersey collaborated with these colleagues on this research: Weili Chen, Quanzhi Li, Ph.D., Wendy Hudson, Ashish Kumar, M.D., Ph.D., and Nicole Kirchhof, all with the Masonic Cancer Center. The research was funded by a grant from the National Institutes of Health (NIH) and the Children's Cancer Research Fund (CCRF).

The Masonic Cancer Center is part of the University of Minnesota. It is designated by the National Cancer Institute as a comprehensive cancer center. Its researchers and staff perform basic, clinic, and population research; provide treatment to cancer patients; and present education programs. For more information about cancer and the Masonic Cancer Center, call the information line at 612-624-2620 or toll-free in the five-state area at 1-888-CANCER MN (1-888-226-2376) or visit www.cancer.umn.edu.

Media Contact: Mary Lawson, Public Relations Director, Masonic Cancer Center, 612-624-6165, 612-363-6971 (cell), mlawson@umn.edu.