Few things are as tiresome as house hunting and moving. Unfortunately, metastatic cancer cells have the relocation process down pat. Tripping nimbly from one abode to another, these migrating cancer cells often prove far more deadly than the original tumor.
Although little has been known about how these rogue cells choose where to put down roots, researchers at the Stanford University School of Medicine have now learned just how nefarious they are.
"Metastasis is not a passive process," said cancer biologist Amato Giaccia, PhD. "Cells don't just break off the primary tumor and lodge someplace else. Instead the cells actually secrete substances to precondition target tissue and make it more amenable to subsequent invasion."
In other words, the cells plan ahead by first sending molecular emissaries to orchestrate a breach in the body's natural defenses. Blocking this cascade of events in mice hobbled the cells' migration and prevented the metastatic cancer that developed in control animals. The researchers are hopeful that a similar tactic will be equally successful in humans.
Giaccia, the Jack, Lulu and Sam Willson Professor and professor of radiation oncology at Stanford, is the senior author of the research, which will be published in the Jan. 6 issue of Cancer Cell. Giaccia is also a member of the Stanford Cancer Center.
Scientists have known for some time that certain primary cancers metastasize preferentially to other organs — breast cancer often spreads to the lungs, for example. This is in part due to the patterns of blood flow in the body. They also knew that such future colonization sites, called pre-metastatic niches, harbor large numbers of cells derived from the bone marrow that somehow facilitate the cancer cells' entry. What they didn't know is how the bone-marrow-derived cells were summoned, and what, if any, role the primary tumor cells played in site selection.