Lack of interstitial chromosome 1p deletions in clinically-detected neuroblastoma

Loss of heterozygosity (LOH) of the distal part of the short arm of chromosome 1 in neuroblastoma is a well characterised phenomenon. In addition, previous reports have described interstitial deletions outside the common region of loss on chromosome 1p36, suggesting additional tumour suppressor loci. In this study, we have searched extensively for interstitial 1p deletions in a panel of 67 neuroblastoma samples from clinically-detected cases. We used three VNTR probes and 10 dinucleotide markers from the 1p32-36 regions reported to show interstitial deletions. Fifteen (22%) tumours showed telomeric LOH without evidence for more proximal interstitial deletions. Forty-five tumours showed no LOH or allelic imbalance. Seven (10%) tumours demonstrated allelic imbalance for one or more markers. These tumours were subsequently analysed by fluorescent in situ hybridisation (FISH) and flow cytometry. The patterns found in all seven tumours were consistent with copy number changes of the entire chromosome 1, without evidence for interstitial deletions. This study indicates that interstitial deletions of chromosome 1p are rare in clinically-detected neuroblastoma when analysed by a combination of molecular and cytogenetic techniques.