[1] St James Univ Hosp, Leeds Inst Canc & Pathol, Leeds LS9 7TF, W Yorkshire, England
[2] St James Univ Hosp, Yorkshire Reg Cytogenet Unit, Leeds LS9 7TF, W Yorkshire, England
[3] Ohio State Univ, Med Ctr, Dept Neurosurg, Columbus, OH 43210 USA
[4] Harvard Univ, Sch Med, Brigham & Womens Hosp, Dept Neurosurg, Boston, MA 02115 USA