Abstract: Objective The loss of NF2 gene in cutaneous schwannomas of neurofibromatosis type 2 patients was investigated in order to explore the tumorigenesis and characteristics of NF2 tumor suppressor gene, and to provide evidence for presymptomatic gene diagnosis for NF2 patients. Methods DNA was extracted from whole blood and frozen tumor tissue, respectively. Genotyping was performed using 6 microsatellite markers flanking or within the NF2 gene:CRYB2-D22S193-NF2CA1-NF2CA3-D22S268-D22S430, which is tightly linked to the NF2 gene and analyzed on an ABI Genetic Analyzer 310 after PCR amplification. Results A total of 18,14,0,13,16,12 samples showed loss of heterozygosity at microsatellite markers CRYB2, D22S193, NF2CA1, NF2CA3, D22S268, D22S430 in 43 samples of cutaneous schwannomas, respectively. Conclusions The method for detection of NF2 allelic loss was established. Frequent allelic loss reconfirms that NF2 gene is a tumor suppressor gene. The observation that tumors with or without allelic loss of the NF2 gene exist in the same patient indicates that these tumors are originated from different clones in which genetic alterations occurred independently.

Key words: Neurofibromatosis 2, Neurilemmoma, Genes,neurofibromatosis 2, Microsatellite repeats, Loss of heterozygosity