LOSS OF NEUROFIBROMIN IN ADRENAL-GLAND TUMORS FROM PATIENTS WITH NEUROFIBROMATOSIS TYPE-I

The neurofibromatosis type 1 gene encodes a protein, neurofibromin, wh ich may function as a tumor suppressor gene product. Recent studies ha ve demonstrated loss of neurofibromin in tumors from NF1 and non-NF1 p atients, including neurofibrosarcomas, neuroblastomas and malignant me lanomas. Since neurofibromin is expressed in the adrenal gland, six ph eochromocytomas and one adrenal cortical tumor were examined for neuro fibromin expression. In all seven tumors, no neurofibromin could be de tected. Furthermore, loss of heterozygosity (LOH) analysis demonstrate d that in one of the pheochromocytomas, reduction to homozygosity was observed for both 17p and 17q markers while the adrenal cortical tumor demonstrated LOH for only 17q markers. The frequent LOH surrounding t he NF1 locus and lack of neurofibromin expression in these tumors sugg est that NF1 gene mutations may contribute to the development of adren al gland neoplasms in patients with NF1. (C) 1994 Wiley-Liss, Inc.