Today the field is divided. Although it seems clear that at least some cancers follow the stem cell model, researchers disagree over which tumors belong in that category. And no one yet knows whether therapies that specifically target cancer stem cells will save lives or how best to identify cancer stem cells. Nor do researchers understand how cancer stem cells originate, how often they derive from normal stem cells or whether each tumor has just a few or many of the cells. Some of the latest study results suggest that a complex mix of both the standard model and the cancer stem cell idea comes closest to elucidating how cancers form.
Despite the controversy, the research is prompting scientists to pay closer attention to the diverse subsets of cells found within all tumors. Ravindra Majeti, a cancer researcher at Stanford University, is working to develop diagnostic tools that indicate how aggressive a particular cancer will be—and therefore what type of treatment is needed—based on which genes are most active in the tumor cells. The hope is that this approach would be a more accurate way to gauge a tumor’s degree of malignancy than the standard method, which involves examining the cells under a microscope and grading them based on their how abnormal they appear.
For now Elliott will continue to take her yellow pills and try to stay positive. “We appreciate everything we do have,” she says, speaking for herself and her fellow patients. “But what we really want is a cure for this and to live a normal life.”
This article was originally published with the title How Do Tumors Grow?.