The finding in experimental models that leukemia stem cells are better at predicting clinical outcome than the majority of acute myeloid leukemia (AML) cells has now been demonstrated in human patients.
According to a statement issued by University Health Network (UHN) in Toronto, Ontario, Canada, in conjunction with the release of the research results, scientists have long debated whether all cells in a tumor are equal, or whether some cancer cells are more potent. The question has been explored in experimental models, but John E. Dick, PhD, of UHN’s Ontario Cancer Institute in Toronto, and colleagues report that they have shown for the first time that leukemia stem cells are significant not just in the experimental models but also in patients.
As the investigators described in Nature Medicine, they identified which of 16 human AML samples contained leukemia stem cells using a sensitive xenograft assay. By sorting, analyzing, and comparing these cells with healthy stem cells and clinical data, Dick’s team uncovered a gene signature that was common to both normal and leukemia stem cells and could accurately predict the course of AML in the patients studied. Persons who strongly expressed the stem cell signature had much shorter survival than did those with low expression of the signature.
“Although our research was on AML, our finding that [leukemia stem cells] are real and relevant in patients set the entire cancer stem cell field on a firmer footing,” commented Dick in the UHN statement.
The genes within the stem cell signature provide new drug targets that could be used to eliminate leukemia stem cells, prevent disease recurrence, and improve overall patient survival. The genes also represent potential AML biomarkers that could be used to identify patients who would benefit from more aggressive therapy; and ultimately could be use to personalize cancer therapy.