1;17 Trauslocations in Neuroblastoma 535 cosmid cl02 (CEBlS) (Dr G. Vergnaud), YAC clone A230A7 (ERBB2) van Gezwelziekten vzw”, the European Concerted Action on Molecular (Dr C. Lengauer), cosmid 7G4 (NFZ) (Dr S. Watkins). Cytogenetics of Solid Tumours (PL920156), and the “Stichting voor We gratefully acknowledge the financial support of the “Vereniging Kindergeneeskundig Kankeronderzoek zyxwvutsrqponmlkjihgfedcbaZYX (SKK)“. voor Kankerbestrijding’ “Het Centrum voor de Studie en Behandeling Pergamon Europemrfoumal of Cancer Vol. 31A, No. 4, pp. 53%538,1995 Ekvier Science Ltd Printed in Great Britain 0959-8049/95$9.50+0.00 A Multiplex PCR Assay for Routine Evaluation of Deletion of the Short Arm of Chromosome Neuroblastoma 1 in G. Schleiermacher, M. Peter, J. Michon, J.-M. Zucker, G. Thomas, H. MagdelCnat and 0. Delattre Deletions of the short arm of chromosome 1 (lp) are frequent alterations in neuroblastoma. Although a consensus region of deletion has bleen mapped to chromosome subband 1~36, recent studies suggest that several distinct loci on this chromosome may be involved in neuroblastoma. Moreover, different patterns of deletion might be associated with different clinical and biological characteristics of the turnouts. These findings emphasise the importance of as’sessing the localisation and the extent of the deletions in neuroblastoma. We developed a technique which allows analysis of loss of heterozygosity at multiple loci on lp in a single step, making use of a multiplex PCR method. Primers specific for six microsatellite loci mapped in the different regions of interest on lp were used for simultaneous amplification of DNA, and loss of heterozygosity was determined after separation of the alleles by denaturing polyacrylamide gel electrophoresis. This technique enables a simple analysis of the position and extent of lp deletions, and can be used for routine evaluation of lp status in neuroblastoma. Key words: neuroblastoma, chromosome 1, short arm, deletion, loss of heterozygosity, PCR, microsatellite, prognosis EurJ Cancer, Vol. 31A, No. 4, pp. 535-538,1995 INTRODUCTION NEUROBLASTOMA, a tumour derived from neural crest tissue, is the most frequent extracranial solid tumour in childhood and presents a wide variability ofits clinical course. It is characterised by two main genetic alteralions: amplification of the oncogene MYCN is found in 25-30% of the cases and deletion of the short arm of chromosome 1 (lp), as detected by molecular studies, is observed in 3UO% of tuunours [l-3]. Both alterations are detected more frequently in advanced stages of disease and have been associated with a poor outcome [4-71. Initial molecular studies suggestedlthat deletions encompassed a single region of overlap located in the 1~36.2-3 subband [2, 81. However, recent observations indicate that, in addition to this Correspondence to Olivier Delattre. G. Schleiermacher, M. Peter and H. MagdelCnat are at the Laboratoire de Transfert; G. Schleiermachtr, J. Michon and J.-M. Zucker are at the Service de PCdiatrie; and G. Thomas and 0. Delatrre are at the Laboratoire de G&&ique des ‘Tumeurs, INSERM 434. Institut Curie, 26 rue d’Ulm, 75231 Paris Cedex 01, France. locus, other loci on lp might be involved in the tumorigenesis of neuroblastoma. Indeed, deletions limited to the 1~36.2-3 subband are not associated withM YCN, whereas this association is observed for larger deletions [9, 1I]. Moreover, preferential loss of maternal alleles has been demonstrated in the former deletions, but not in the latter [ 121. These observations suggest that at least two different loci on lp are involved in tumours. Indication of an additional locus is provided by interstitial deletions which define a second short region of overlap located more proximally on lp [9]. Finally, preliminary clinical reports suggest that the prognostic information provided by lp deletion might depend on its size and localisation [lo]. These findings emphasise the importance of the determination of the extent and of the chromosome position of deletions in neuroblastoma. We have developed a method which allows detection of a deletion on lp in neuroblastoma, determination of its localisation and estimation of its size. This method, which is based on the multiplex PCR amplification of microsatellite loci, enables the determination of these parameters, in a single step, on small tumour samples.