Preferential amplification of the paternal allele of the N-myc gene in human neuroblastomas.

Genomic imprinting plays a role in influencing the parental origin of genes involved in cancer-specific rearrangements. We have analysed 22 neuroblastomas with N-myc amplification to determine the parental origin of the amplified N-myc allele and the allele that is deleted from chromosome 1p. We analysed DNA from neuroblastoma patients and their parents, using four polymorphisms for 1p and three for the N-myc amplicon. We determined that the paternal allele of N-myc was preferentially amplified (12 out of 13 cases; P = 0.002). However, the paternal allele was lost from 1p in six out of ten cases, consistent with a random distribution (P > 0.2). These results suggest that parental imprinting influences which N-myc allele is amplified in neuroblastomas, but it does not appear to affect the 1p allele that is deleted in the cases that we have examined.