CHARACTERIZATION OF THE CHROMOSOME BREAKPOINTS IN A PATIENT WITH A CONSTITUTIONAL TRANSLOCATION T(1-17)(P36.31-P36.13-Q11.2-Q12) AND NEUROBLASTOMA

Cytogenetic and molecular studies in neuroblastoma suggest the presenc e of a tumour suppressor gene at the distal chromosome band 1p36. Prev iously, we hypothesised that a constitutional translocation involving the region 1p36 [t(1;17)(p36;q12-q21)] in a patient with neuroblastoma predisposed him to tumour development. Here we report the molecular d elineation of the translocation breakpoints. Somatic cell hybrids cont aining the derivative chromosomes were used to determine the position of chromosome 1p and 17q DNA probes respective to the breakpoints usin g fluorescence in situ hybridisation. The 1p breakpoint was localised between the PND and D1S56loci. The chromosome 17q breakpoint is flanke d by NF1 and SCYA7, as proximal and distal marker, respectively. We re defined the translocation as t(1;17)(p36.31-13;q11.2-q12). The identif ication of flanking markers of the breakpoints is a prerequisite for b reakpoint cloning and identification of a putative neuroblastoma suppr essor gene.