Researchers at the Stanford University School of Medicine have revealed that a molecule called telomerase, best known for enabling unlimited cell division of stem cells and cancer cells, has a surprising additional role in the expression of genes in an important stem cell regulatory pathway.

The unexpected finding may lead to new anticancer therapies and a greater understanding of how adult and embryonic stem cells divide and specialize.

"Telomerase is the factor that accounts for the unlimited division of cancer cells," said Steven Artandi, MD, PhD, associate professor of hematology, "and we're very excited about what this connection might mean in human disease." Artandi is the senior author of the research, which will be published in the July 2 issue of the journal Nature. He is also a member of Stanford's Cancer Center.

In many ways, telomerase is the quintessential molecule of mystery — hugely important and yet difficult to pin down. Telomerase was known to stabilize telomeres, special caps that protect the ends of chromosomes. It stitches short pieces of DNA on these chromosome ends in stem cells and some immune cells, conferring a capacity for unlimited cell division denied to most of the body's other cells. Its importance is highlighted by the fact that it is inappropriately activated in more than 90 percent of cancer cells, suggesting that drugs or treatments that block telomerase activity may be effective anticancer therapies. However, its vast size, many components and relative rarity — it is not expressed in most of the body's cells — hinder attempts to learn more about it.