Medical and health experts have always recognized a connection between the prenatal growth of a fetus and the presence of cancerous cells in tissue, but have been unable to match the genesis of this link.

Researchers from the Eunice Kennedy Shriver National Institute of Child Health and Human Development say they have stumbled upon across a protein that may trigger both processes.

The insulin-like growth factor 2 gene, IGF2, plays an essential role in fetal development and also promotes the proliferation of cells in tissue. In the past, experts have been puzzled by what it is that allows IGF2 to turn itself on and off at different times in someone's life.

NICHD researchers Dr. Julian C. Lui and Dr. Jeffrey Baron analyzed the tissue of both humans and mice to decide what caused the sudden stimulation of this gene.

"We've long known that some of the genes that promote rapid growth in prenatal and early postnatal life become reactivated in cancer cells," said Dr. Baron.

"Now we've identified a molecular switch that appears to turn on some of these genes, taking us a step forward in understanding normal body growth and the abnormal growth in some types of cancer."

The two co-authors of this study found a protein in humans known as E2F3 that may control the activation of the IGF2 gene. The team found evidence that this protein controls the function of many genes in tissue, including IGF2.

Drs. Liu and Baron added in their report, "When E2F3 levels are high, these genes are active. When E2F3 takes a dive, so do these genes."

Further evaluation of this protein could answer a number of questions concerning normal development and the origin of various types of cancer.

The entire study, conducted by the National Institutes of Health, is featured in Tuesday's edition of the Proceedings of the National Academy of Sciences.