“We identified a subset of brain tumor cells that are slower growing or remain at rest, and appear to be the source of cancer recurrence after standard therapy in which the drug temozolomide is given to stop the tumor’s growth,” said Dr. Luis Parada. “Current therapy targets fast-growing tumor cells but not those responsible for new tumors. To the best of our knowledge, this is the first identification of a cancer stem-like cell in a spontaneously forming tumor inside a mammal.”