Nonetheless, this 'epiphany' about the nature of cancer drives the direction of Dr. Zambidis’ research. Made less than a decade ago, it’s a discovery that may one day revolutionize how childhood cancers are treated. The key to curing cancer, Dr. Zambidis explains, is in understanding stem cells, the building blocks of the human body that give rise to all other cells.
“We believe that at the root of cancer is a stem cell gone bad. These stem cells get genetic mutations that cause them to divide uncontrollably, instead of developing into normal healthy cells,” Dr. Zambidis says.
While Dr. Zambidis is careful to explain that this theory is still very much at the discovery phase, there’s an undeniable note of excitement in his voice when he discusses its potential. “We’re not at the stage where we can translate this knowledge into cures, at least not yet,” he says.
For now, Dr. Zambidis’ laboratory has invested heavily in stem cell research in the hopes of eventually unleashing its potential: the ability to kill the stem cells that give rise to cancer. But to reach this point, explains Dr. Zambidis, scientists must first better understand the mechanics of normal stem cells. His group studies the very earliest normal stem cells of the body, called embryonic stem cells, which he believes share secret mechanisms hijacked by abnormal cancer stem cells when they divide uncontrollably.
That understanding will require extreme perseverance, and an equal amount of patience. Considering how far the field of pediatric oncology has come in the last fifty years helps put the journey in perspective. “Most patients we take care of have fantastic outcomes. That was not the case in the ‘60s and ‘70s. But despite an 80 percent survival rate for most childhood leukemias, we still have a long way to go,” Dr. Zambidis says.
In addition to increasing the survival rate, Dr. Zambidis and his colleagues are committed to improving the way that children are cured of cancer. “Most of our treatments remain the ‘old’ way: Give the body a bunch of poisons that kill most but not all of the cancer cells, but also cause significant side effects in the patient. Many cancers return because there are rare cancer stem cells that invade the majority of the tumor, and most chemotherapies do not target or kill these rare cells. Now we realize it’s not the “soldiers” that are the problem; it’s the “generals” (the stem cells) we should be attacking,” he says.
Though the task ahead looms large, Dr. Zambidis expresses confidence in his colleagues at the Kimmel Center, as well as the highly active international network of researchers working to improve survival rates and quality of life for children with cancer under the umbrella of the Children's Oncology Group. "There have been a phenomenal number of clinical trials for pediatric cancer patients between the '70s and now. Almost every child, wherever they are newly diagnosed with cancer in this country, is ostensibly enrolled in a trial," he says. "We are constantly learning, revising, and improving the cancer care of our patients based on what we learn from such trials."
This deep commitment to furthering the science of pediatric oncology suggests that, at its source, is a subject tremendously inspiring to physician-scientists like Dr. Zambidis. He always knew he wanted to be a scientist. It wasn't until medical school that he discovered how much he enjoyed interacting with children. Now he has four young children of his own, and he is reminded daily not only at work, but also at home, of the blessing and privilege of caring for children.
"We're not anywhere near done with this mission," Dr. Zambidis says.