Removal of the gene, hippo, resulted in tumor formation in every organ of the fruit fly. The findings, which are currently online, will appear in an upcoming issue of Cell.

"This is one of the few genes that has been discovered that directly controls two pathways, cell proliferation and cell apoptosis, or cell death," said Dr. Duojia Pan, assistant professor of physiology and senior author of the study. "Sustained growth of cancer cells requires activation of the cell proliferation machinery and suppression of a system called the apoptotic failsafe mechanism. The combination of suppressed cell death and deregulated cell production is likely a key element in cancer."

The researchers identified hippo by screening the fruit fly, or drosophila, genome for mutations that promoted abnormal tissue growth.

To determine the relationship between hippo and a similar protein found in humans, the researchers replaced the tumor-suppressor gene in fruit flies with a protein in humans called MST2. This resulted in the reduction of tumors in the fruit flies, leading researchers to hypothesize that MST2 plays a similar role in human-tumor suppression.

"We hypothesize that this protein (MST2) may be inactivated in some humans, causing the onset of tumor growth. Tumor suppression is important in humans because it is required to restrict abnormal growth of tissues," said Dr. Pan, the Virginia Murchison Linthicum Scholar in Medical Research.

The researchers report also that hippo is linked to two other tumor-suppressing genes, Salvador and warts.

"These three tumor-suppression genes may define a tumor su
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Contact: Amy Shields
amy.shields@utsouthwestern.edu
214-648-3404
UT Southwestern Medical Center
16-Jul-2003