Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: FRIDAY, February 12, 1993 TAG: 9302120029
SECTION: NATIONAL/INTERNATIONAL PAGE: A-5 EDITION: METRO
SOURCE: Associated Press
DATELINE: WASHINGTON LENGTH: Medium
GENE FLAW, LEUKEMIA LINKED
A genetic defect may allow cells to take off on a wild growth spurt that leads eventually to adult leukemia, say researchers. The finding holds the promise of a test for leukemia risk.Dr. Cheryl L. Willman of the University of New Mexico School of Medicine reports in the journal Science that it may take the loss of only half of the normal pair of IRF-1 genes to start a process that leads to leukemia.
She said in an interview that a missing or malfunctioning IRF-1 gene was found in the cells of each of 13 patients who had adult leukemia or a condition called myelodysplasia that leads to leukemia.
"Our hypothesis is that if you lose a single allele [half of a pair of genes] it can lead to unrestrained cell growth," she said. Rapidly dividing cells cause a higher rate of mutation and "can cause a promotion to full-blown leukemia," said Willman.
The IRF-1 gene, located on chromosome 5, causes cells to secrete a protein that regulates cell division. It represses the action of a protein that is expressed by another gene, called IRF-2, that promotes cell division. IRF stands for interferon regulatory factor.
A companion paper in Science by scientists at the Osaka University in Japan reports that tumors quickly develop in laboratory mice if there is a surplus of the IRF-2 protein or a shortage of the IRF-1 protein. In effect, the study found that if the two proteins are out of balance, then cancers can form.
Willman said it appears that a balance of the two proteins is lost if only one of the two IRF-1 genes is missing, damaged or malfunctioning.
She said her studies show that a single IRF-1 gene is deleted in patients with myelodysplasia, a condition that appears for some years in older adults before they develop leukemia.