1. Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, 0317 Oslo, Norway
2. Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, University of Oslo, 0318 Oslo, Norway
3. Department of Tumor Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, 0379 Oslo, Norway
4. Department of Neurology, Pathology and Cell Biology, Columbia University, New York, NY 10032-3784, USA
5. Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, 0379 Oslo, Norway