Scientists have identified a population of human colon cancer stem cells that can initiate tumor growth and differentiate into mature tumors, according to two reports in Nature.

These cells, representing just two to three percent of the overall tumor, should be the focus of cancer therapies, according to Ruggero De Maria, research director, Department of Hematology and Oncology, Istituto Superiore di Sanita, Rome, who led one of the two research teams.