Analisi molecolare della malattia midollare ed ematica in pazienti affetti da neuroblastoma

Neuroblastoma (NB) is the most common extracranial solid tumor of childhood. Prognosis for patients with metastatic NB remains grim due to the achievement of remissions of short duration followed by lethal tumor recurrence. Contributory factors to the latter event are the persistence of malignant cells in the bone marrow and, possibly, the reinfusion of tumor cells present in blood aphereses administered to the patients to reconstitute the hematopoietic system following high dose chemotherapy. The methods presently used to detect minimal residual disease, i.e. the neoplastic cells that persist in the host following treatment, are of limited sensitivity. Thus, novel highly sensitive and specific techniques are warranted. Molecular analysis by RT-PCR may be one of these techniques. Thus, the genes coding for tyrosine hydroxylase (TH) and pgp9.5 are expressed in nueroblastoma cells but not in hematopoietic cells. In 1997, we have started a study aimed at comparing different methods for the analysis of tumor cell contamination in the bone marrow and in the peripheral blood. Our results indicate that molecular techniques are superior to other methodologies as for the detection of malignant neuroblasts i) in the peripheral blood and aphereses and ii) in the bone marrow, either during or after chemotherapy administration. We are now defining the best experimental conditions to apply the real-time PCR technology to quantitative investigation of minimal residual disease in NB.