“Zombies have this incredible tendency to just come back to life,” said Wechsler-Reya, who leads the Tumor Development Program at Sanford-Burnham Medical Research Institute. The only way to really kill a zombie is to shoot it in the brain. This is the same strategy we need to take when combating cancer. We have to shoot at the brain of the cancer, the so-called cancer stem cell.”Cancer stem cells are small groups of cells that can become dormant, enhancing their ability to survive the most aggressive radiation and chemotherapy treatments. Later, they can differentiate into more recognizable cancer cells and reconstitute a tumor.
Wechsler-Reya is looking for ways to seek out and destroy these cells in medulloblastoma, the most common form of childhood brain tumor. Unlike zombies, cancers don’t have obvious heads to aim for. But through painstaking research, the Wechsler-Reya lab has found proteins, such as the whimsically-named Hedgehog, CD15 and others, that mark these cancer cells and can be targeted to eliminate them.
Working a few blocks away at UC San Diego, Catriona Jamieson is also gunning for cancer stem cells—in leukemia. Jamieson helps lead a CIRM Disease Team, which has found its own set of cancer stem cell markers, some unique to leukemia. For Jamieson, who works closely with patients, the need to eliminate cancer stem cells could not be more urgent.
“These bad seeds, these dormant seeds, need to be targeted,” said Jamieson during the same World Stem Cell Summit panel. “They’re like houseguests that never want to leave.”For Jamieson and Wechsler-Reya, years of work on cancer stem cells is bearing fruit in clinical trials. Jamieson's CIRM-funded work has already led to three therapies for blood cancers that are currently in clinical trials.