RT Journal Article SR Electronic T1 Gene amplification in PNETs/medulloblastomas: mapping of a novel amplified gene within the MYCN amplicon JF Journal of Medical Genetics JO J Med Genet FD BMJ Publishing Group Ltd SP 501 OP 509 DO 10.1136/jmg.37.7.501 VO 37 IS 7 A1 Michael C Frühwald A1 M Sue O'Dorisio A1 Laura J Rush A1 Jill L Reiter A1 Dominic J Smiraglia A1 Gail Wenger A1 Joseph F Costello A1 Peter S White A1 Ralf Krahe A1 Garrett M Brodeur A1 Christoph Plass YR 2000 UL http://jmg.bmj.com/content/37/7/501.abstract AB OBJECTIVES The pathological entity of primitive neuroectodermal tumour/medulloblastoma (PNET/MB) comprises a very heterogeneous group of neoplasms on a clinical as well as on a molecular level. We evaluated the importance of DNA amplification in medulloblastomas and other primitive neuroectodermal tumours (PNETs) of the CNS. METHOD Restriction landmark genomic scanning (RLGS), a method that allows the detection of low level amplification, was used. RLGS provides direct access to DNA sequences circumventing positional cloning efforts. Furthermore, we analysed several samples by CGH. DESIGN Twenty primary medulloblastomas, five supratentorial PNETs, and five medulloblastoma cell lines were studied. RESULTS Although our analysis confirms that gene amplification is generally a rare event in childhood PNET/MB, we found a total of 17 DNA fragments that were amplified in seven different tumours. Cloning and sequencing of several of these fragments confirmed the previous finding ofMYC amplification in the cell line D341 Med and identified novel DNA sequences amplified in PNET/MB. We describe for the first time amplification of the novel gene,NAG, in a subset of PNET/MB. Despite genomic amplification, NAG was not overexpressed in the tumours studied. We have determined thatNAG maps less than 50 kb 5′ ofDDX1 and approximately 400 kb telomeric ofMYCN on chromosome 2p24. CONCLUSION We found a similar but slightly higher frequency of amplification than previously reported. We present several DNA fragments that may belong to the CpG islands of novel genes amplified in a small subset of PNET/MB. As an example we describe for the first time the amplification ofNAG in the MYCNamplicon in PNET/MB.