COMPETITIVE POLYMERASE CHAIN-REACTION FOR THE QUANTIFICATION OF N-MYCGENE COPY NUMBER IN NEUROBLASTOMA

An absolute quantification method for the N-myc gene copy number of ne uroblastoma specimens was established by applying the competitive poly merase chain reaction (cPCR). The competitor plasmid (pZH2) lacking an MluI site in the exon 2 was constructed to distinguish two product sp ecies amplified from genomic DNA and the competitor plasmid. By using this cPCR system, we could obtain qualitative results within 1 day, i. e. amplified or unamplified, and quantitative results by using radiola belled nucleotides within 4 days. The copy numbers of N-myc in 47 neur oblastoma specimens by cPCR correlated well with those by Southern hyb ridization (r = 0.85). We conclude that cPCR is a simple and rapid met hod, requires only a Amplification small amount (200 ng) of sample DNA , and is expected to be Neuroblastoma used for prognostic evaluation i n neuroblastomas.