Allelic loss of chromosome 1p36 in neuroblastoma is of preferential maternal origin and correlates with N-myc amplification

Neuroblastomas frequently have deletions of chromosome 1 p and amplification of the N–myc oncogene. We analysed 53 neuroblastomas for the N–myc copy number, loss of heterozygosity (LOH) of chromosome 1 p36 and the parental origin of the lost alleles. Allelic loss of 1p36 was found in 15 tumours. All N–myc amplified tumours belonged to this subset. In 13/15 tumours with LOH of 1 p36 the lost allele was of maternal origin. This non–random distribution implies that the two alleles of the putative neuroblastoma suppressor gene on chromosome 1p36 are functionally different, depending on their parental origin. This is the first evidence as far as we know for genomic imprinting on chromosome 1p.