A new role for a protein involved in leukaemia is described in Nature this week; the research demonstrates its potential as a therapeutic target to eradicate dormant leukaemia-initiating cells.

The promyelocytic leukaemia protein (PML) tumour suppressor is known to be involved in the development of some forms of leukaemia. Pier Paolo Pandolfi and colleagues identify a new and unexpected role for PML in the maintenance of both haematopoietic stem cells and leukaemia-initiating cells. They demonstrate, in mice, that targeting the protein with arsenic trioxide eliminates the cancer-initiating cells, thought to be resistant to chemotherapy and other therapies.

The team believes that their results present a new pharmacological approach to target cells that are missed by other therapies and therefore lead to disease relapse.