In general, cancer begins with a genetic mutation that allows normal, healthy cells to continue growing without responding to the signals to stop, which normal cells do. Cancer cells grow and multiply out of control. The accumulating abnormal cells form a mass (tumor).

Neuroblastoma begins in neuroblasts — immature nerve cells that a fetus makes as part of its development process.

As the fetus matures, neuroblasts eventually turn into nerve cells and fibers and the cells that make up the adrenal glands. Most neuroblasts mature by birth, though a small number of immature neuroblasts can be found in newborns. In most cases, these neuroblasts mature or disappear. Others, however, form a tumor — a neuroblastoma.

It isn't clear what causes the initial genetic mutation that leads to neuroblastoma.

Nov. 20, 2012