Researchers at the University of Pennsylvania have identified a gene that appears to cause a common form of childhood cancer.

Neuro-blastoma is a cancer of the nervous system, and has a strong family association.

Researchers studied the genes of 20 affected families. They identified a genetic mutation that caused the disease in a majority of families; this mutation was also spotted in sporadic cases of the disease.

Researchers have also identified a cause of another childhood cancer, called medullo-blastoma.

About 250 to 300 children will develop this disease each year. Most survive, but they are often left with disabilities. The study, conducted at Dana Faber Cancer Institute, looked at signaling pathways in the brain and their interaction with certain cells. They found when one particular pathway connected with brain stem cells, tumors were triggered.

Researchers now want to learn what it is about these cells that makes them develop tumors when stimulated by this pathway.