1. Institut National de la Santé et de la Recherche Médicale Unit 344 (B.K.L., N.B., P.A.K.), Endocrinologie Moléculaire, Faculté de Médecine Necker, 75730 Paris Cedex 15, France;
2. Cancer Research Program (C.J.O.), Garvan Institute of Medical Research, Darlinghurst NSW2010, Sydney, Australia;
3. Tufts University School of Veterinary Medicine (R.S.B.), Department of Biomedical Sciences, North Grafton, Massachusetts 01536