HBV GENE CAUSES LIVER CANCERResearchers have shown directly that hepatitis B virus (HBV)causes liver cancer.
Seventy-five percent of transgenic mice containing a singleHBV gene developed liver cancer following the same pattern oftumor development as humans. The mice, described in lastweek's issue of Nature, can be used to study the mechanisms ofliver cancer progression.
The finding will likely provide impetus to the Centers forDisease Control's recommendation that infants be routinelyvaccinated against HBV. HBV strikes about 300,000 people inthe United States annually. Merck and SmithKline Beechamshare the HBV vaccine market.
Until now, a lot of epidemiological evidence had suggested alink between HBV and liver cancer. But there was no proof thatHBV actually caused cancer.
Scientists at the American Red Cross in Rockville, Md., andNational Institute of Health in Tokyo introduced the HBV HBxgene into mice. This gene induced cancer development, possiblyby activating genes that promote cell growth. The HBx proteinnormally switches on the expression of HBV genes during viralinfection. -- Carol Talkington Verser, Ph.D.
IGF-I MAY BE USED TO TREAT SHORT STATURE
A preliminary study suggests that insulin-like growth factor I(IGF-I) may be useful in promoting the growth of patients withgrowth hormone (GH) insensitivity syndrome.
Patients with this syndrome, also called Laron dwarfism, do notrespond to growth hormone treatment, probably due todefective GH receptors. These patients do not produce IGF-I,which carries out GH's growth-promoting activities.
Researchers at the University of North Carolina and the ChildHealth Center in Warsaw, Poland, infused Genentech Inc.'s IGF-I into a GH-insensitive short child for 11 days. The doctorschose to infuse IGF-I since large injections of the insulin-likeprotein lead to low blood sugar.
IGF-I led to metabolic changes in the patient that mimickedGH's effect in patients that are sensitive to GH, the researchersreported Thursday in the New England Journal of Medicine.Longer-term studies will determine whether IGF-I acceleratesgrowth in these patients.
Genentech provided IGF-I for the study, but is not developingit for this indication, said spokeswoman Susan Rogers.
The South San Francisco, Calif., company is in early clinicaltrials to test IGF-I as a treatment for nutrition-relatedmetabolic disorders and for diabetes, she said.
Other companies developing IGF-I include Chiron Corp. withCiba-Geigy, Creative Biomolecules Inc. and Eli Lilly & Co.BioGrowth Inc. is developing an IGF-I binding protein to blockIGF-I's insulin-like effects and to increase its half-life in theblood stream. -- CTV
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