Loss of Y Chromosome in the Malignant Peripheral Nerve Sheet Tumor of a Patient with Neurofibromatosis Type 1

Neurofibromatosis type 1 (NF1) is one of the most commonly inherited autosomal dominant disorders. In order to determine whether genomic alterations and/or chromosomal aberrations involved in the malignant progression of NF1 were present in a Korean patient with NF1, molecular and cytogenetic analyses were performed on the pathologically normal, benign, and malignant tissues and primary cells cultured from those tissues of the patient. The comparative genomic hybridization (CGH) array revealed a Y chromosome loss in the malignant peripheral nerve sheet tumor (MPNST) tissue. G-banding analysis of 50 metaphase cells showed normal chromosomal patterns in the histopathologically normal and benign cultured cells, but a mosaic Y chromosome loss in the malignant cells. The final karyotype for the malignant cells from MPNST tissue was 45,X,-Y[28]/46,XY[22]. The data suggest that the somatic Y chromosome loss may be involved in the transformation of benign tumors to MPNSTs.