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 amplifi cation 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 1 p36 was fou nd 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 or igin. This non-random distribution implies that the two alleles of the putative neuroblastoma suppressor gene on chromosome 1 p36 are functi onally different, depending on their parental origin. This is the firs t evidence as far as we know for genomic imprinting on chromosome 1 p.