FLUORESCENCE IN-SITU HYBRIDIZATION ANALYSIS OF CHROMOSOME 1P36 DELETIONS IN HUMAN MYCN AMPLIFIED NEUROBLASTOMA

Background/Purpose: Deletion of the short arm of chromosome 1 (1p) is one of the poor prognostic factors in human neuroblastomas. Recent Stu dies have suggested that one or more of the neuroblastoma tumor suppre ssor genes reside in this region and have identified the shortest regi on of overlap (SRO) on 1p36. The purpose of this study was to examine deletions of 1p in human neuroblastomas by fluorescence in situ hybrid ization (FISH). Methods: Two-color FISH analysis was performed to dete ct chromosome 1p36 abnormalities in 42 MYCN-amplified neuroblastomas. Four different probes from the 1p36 region, the E2F2 NPPA, D1S160, and CDC2L1 loci were used for detection of 1p abnormalities. A repeat seq uence probe, which is specific for the heterochromatic region of chrom osome 1 (pUC1.77), was used as a control. Results: Large deletions of 1P36 were observed in 31 (73.8%) of 42 tumors, whereas the remaining 1 1 (26.2%) showed no deletion. In these 11 tumors, a translocation of 1 p was found in one and a duplication of 1p was detected in another. Co nclusions: A strong correlation between 1p abnormalities and MYCN ampl ification was found in this study. MYCN-amplified neuroblastomas were found to show large deletions of 1p encompassing the SRO. FISH provide d a rapid and reliable method to detect hemizygous deletions of 1p.