Researchers at Johns Hopkins, Baltimore, and Ohio State University, Columbus have found the number of copies of a particular gene can affect the severity of colon cancer in a mouse model. The research team describes how trisomy 21, or Down syndrome in humans, can repress tumor growth.

"We took a new approach to a 50-year-old debate about whether people with Down syndrome develop cancer less often than other people," says Roger H. Reeves, PhD, professor of physiology in the McKusick-Nathans Institute of Genetic Medicine at Hopkins. "Studying the genetic differences associated with Down syndrome has revealed a new way of thinking about repressing cancer growth in everyone."

The research team started with a mouse model carrying, rather than a whole extra copy of chromosome 21 as is seen in trisomy 21, or Down syndrome, a partial copy containing 108 genes. They then mated those trisomic mice to mice carrying a mutation causing intestinal tumors, similar to those seen in colon cancer in humans. The trisomic, colon cancer mice had 44 percent fewer intestinal tumors compared to the colon cancer mice without the extra 108 genes.

There is a high prevalence of chronic kidney disease in the U.S., which has risen over the past decade, according to a study led by researchers at the Johns Hopkins Bloomberg School of Public Health, Baltimore.

The study found the overall prevalence of chronic kidney disease increased from 10 percent of the population during 1988-1994 to 13 percent from 1999-2004. The researchers conclude the increase in chronic kidney disease is partly due to the rise in number of Americans with diabetes and hypertension and the aging of the population.

"Our study demonstrates chronic kidney disease in the U.S. is more common than previously appreciated. However, less than one in 10 individuals with kidney disease are aware they have a problem," said Josef Coresh, MD, PhD, lead author of the study and professor in the Departments of Epidemiology and Medicine at Johns Hopkins University. "The medical community is starting to realize chronic kidney disease is a serious concern, similar to the increased awareness of hypertension in the 1970s and diabetes in the 1990s."