Cancer Genes More Abundant

March 7, 2007 -- Cancer genes may be more abundant than scientists previously thought.

So say cancer gene specialists including P. Andrew Futreal, PhD, co-leader of the Cancer Genome Project at the Wellcome Trust Sanger Institute in Cambridge, England.

Futreal's team is researching the connection between genes and cancer. They're combing through human DNA to look for genetic patterns associated with cancer.

As part of those efforts, Futreal and colleagues screened the DNA from 210 human cancers and from healthy human tissue. They focused on 518 genes that make a type of protein that has been linked to various cancers.

The DNA tests had widely varying results. Of the 210 cancers, 73 had no mutations in the studied genes, while others had "exceptionally large" numbers of mutations, the researchers write in Nature.

Drivers and Passengers

All in all, the scientists spotted more than 1,000 gene mutations in the cancers' DNA.

Most of those mutations apparently don't affect cancer development. The researchers call those mutations "passenger mutations."

However, the scientists also spotted an estimated 158 "driver mutations" that appeared to increase cancer risk. Of the 518 genes studied, nearly 120 had driver mutations, the study shows.

"It turns out that most mutations in cancers are passengers," Futreal says in a Wellcome Trust Sanger Institute news release.

"However, buried amongst them are much larger numbers of driver mutations than was previously anticipated," he continues. "This suggests that many more genes contribute to cancer development than was thought."

The study doesn't show that those gene mutations were the sole cause of cancer. A mix of genetic and environmental factors is thought to affect cancer risk.