1. Department of Physics Norwegian University of Science and Technology (NTNU) Trondheim NO‐7491 Norway
2. Department of Biotechnology and Nanomedicine SINTEF AS Trondheim 7034 Norway
3. Cancer Clinic St.Olavs Hospital Trondheim 7030 Norway
4. Edwin L. Steele Laboratory for Tumor Biology Massachusetts General Hospital Boston MA 02114 USA