Purpose: In patients with neuroblastoma (NB), minimal disease (MD) in bone marrow (BM) and peripheral blood (PB) is thought to play an important role in metastasis. The current study was designed to evaluate the clinical implications of the detection of MD in NB at the initial diagnosis.
Methods: Expression of the neuroendocrine protein gene product 9.5 (PGP9.5) and tyrosine hydroxylase (TH) mRNA in BM and PB obtained from 18 patients with NB was investigated by reverse transcriptase-polymerase chain reaction (RT-PCR).
Results: MD was detected in the BM obtained from 4 of 14 localized NB patients and also in the PB from 2. However, it was found also in both the BM and PB obtained from all 4 patients with metastatic NB. Two of the 4 MD-positive patients with localized NB had metastatic recurrence after a complete tumor excision. They also had unfavorable biological prognostic factors compared with the other 2 who did not have recurrent disease.
Conclusion: MD detected by RT-PCR in the BM and the PB of patients with NB thus suggests a risk for metastatic disease, which in association with other unfavorable biological features may indicate a poor prognosis.