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 gene located at 1p36 has been implicated to play a major role in tumor aggressiveness and clinical prognosis. We have examined 30 different staged primary neuroblastoma tumors using RT-PCR, for expression of the p73 gene located at 1p36.3, and its correlation to other clinical and biological features of these tumors. No correlation between expression of p73 and MYCN-amplification or 1p-deletion could be found, five of ten 1p-deleted tumors showed detectable 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 three 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 neuroblastoma tumors. Furthermore, it suggests absence of correlation between p73-expression and stage in these tumors. In conclusion, we could find no evidence for p73 being the neuroblastoma tumor suppressor gene in 1p36.