ANN ARBOR, Mich---University of Michigan researchers have determined that most types of melanoma cells can form malignant tumors, providing new evidence that the deadliest form of skin cancer does not conform to the increasingly popular cancer stem cell model.
In addition, the researchers found that melanoma tumor cells can change their appearance by switching various genes on and off, making the malignant cells a stealthy, shape-shifting target for researchers seeking new treatments, according to a team led by Sean Morrison, director of the U-M Center for Stem Cell Biology.
Both findings fly in the face of the cancer stem cell model, which states that a handful of rare melanoma stem cells drive the formation, growth and progression of malignant tumors in many cancers. Some supporters of the model have suggested that melanoma might be more effectively treated by taking aim specifically at these rare cancer stems cells, rather than attempting to eliminate all melanoma cells.
But after conducting an exhaustive search for this elusive sub-population of tumor-forming melanoma cell, the U-M team concluded that it probably does not exist. The researchers analyzed 44 sub-populations of human melanoma cells, and all 44 had a similar ability to form tumors when transplanted into mice.
"Some have suggested that melanoma follows a cancer stem cell model in which only rare cells are able to proliferate extensively and form new tumors," said Morrison, a Howard Hughes Medical Institute investigator.
"Our results suggest that most melanoma cells are capable of driving disease progression and that it won't be possible to cure patients by targeting rare sub-populations of cells," Morrison said. "We think you need to kill all the cells."
The team's findings will be published Nov. 16 in the journal Cancer Cell. The first authors of the paper are Elsa Quintana of the U-M Center for Stem Cell Biology, based at the Life
|Contact: Jim Erickson|
University of Michigan