Self-renewal of hematopoietic and leukemic stem cells: a central role for the Polycomb-group gene Bmi-1

Self-renewal of hematopoietic stem cells is vital for the sustained daily production of blood cells. Two recent studies have shown that the Polycomb-group gene Bmi-1 is indispensable for regulation of self-renewal by normal and leukemic stem cells. This identifies Polycomb-group genes as potential targets for therapeutic intervention in leukemia, and possibly other forms of cancer.