Variable expression and absence of mutations in p73 in primary neuroblastoma tumors argues against a role in neuroblastoma development

In neuroblastoma, a childhood tumor of neural crest, a tumor suppressor gen e located at 1p36 has been implicated to play a major role in tumor aggress iveness and clinical prognosis. We have examined 30 different staged primar y neuroblastoma tumors using RT-PCR, for expression of the p73 gene located at 1p36.3, and its correlation to other clinical and biological features o f these tumors. No correlation between expression of p73 and MYCN-amplifica tion or 1p-deletion could be found, five of ten 1p-deleted tumors showed de tectable levels of p73, and no mutations could be detected, neither in the retained alleles nor in any other parts of the material. In five 1p-deleted cases the origin of deletion were determined, two were Of maternal and thr ee of paternal origin. Both tumors with maternal 1p-loss showed detectable levels of p73, whereas the three with paternal loss did not. This suggests that p73 is expressed from the paternal allele only in advanced staged neur oblastoma tumors. Furthermore, it suggests absence of correlation between p 73-expression and stage in these tumors. In conclusion, we could find no ev idence for p73 being the neuroblastoma tumor suppressor gene in 1p36.