1. Laboratory of Stem Cells and Cancer, Université Libre de Bruxelles, Brussels, Belgium.
2. Dermatology Department, Erasme Hospital, Université Libre de Bruxelles, Brussels, Belgium.
3. Institute of Cancer Research, Department of Medicine I, Medical University of Vienna and Comprehensive Cancer Center, Vienna, Austria.
4. WELBIO, Université Libre de Bruxelles, Brussels B-1070, Belgium.