1. Radiumhemmet's Research Laboratory, Cancer Center Karolinska, Department of Oncology-Pathology, Karolinska Institute, S-171 76 Stockholm, 1 and
2. Department of Medical Biochemistry and Microbiology, BMC, Uppsala University, S-751 23 Uppsala, 2 Sweden, and
3. Saitama Cancer Center Research Institute, Kita-adachigun, Saitama 362-0806, 3 and
4. Tokyo Metropolitan Hospital, Bunkyo-ku, Tokyo, 4 Japan