A Comparative Analyisis between Flow Cytometry and RT-PCR Methods for the Detection of Minimal Residual Disease in Neuroblastoma

Purpose: A sensitive assay to detect minimal residual disease in neuroblastoma is necessary for accurate assessment of disease status and optimal treatment. In this study, we compared the usefulness of sensitive methods, flow cytometry and RT-PCR for the detection of minimal residual disease in neuroblastoma. Methods: Eighteen patients who were newly diagnosed and treated at Severance Hospital since 1999 were included in this study. Samples from bone marrow, peripheral blood, and peripheral blood stem cell product were examined for tumor cell contamination by RT-PCR (TH RT-PCR) to detect tyrosine hydroxylase mRNA and by flow cytometry identifying CD9+/CD56+/CD45－ cells. Results: We analyzed 20 cases from 18 patients, which were assayed by both methods at the same time. Among 20 cases, 16 cases showed same results, which were compatible with histologic results and clinical course, and 4 cases showed different results. One case of them showed positive result in histology and flow cytometry, but negative result in TH RT-PCR. The other 3 cases showed negative results in flow cytometry, but positive results in TH RT-PCR, and 1 patient of them relapsed. Among 16 patients, 2 patients, showing positive results in only TH RT-PCR, relapsed. Conclusion: Detection of minimal residual disease using TH RT-PCR and flow cytometry was effective and useful in evaluating disease status and deciding for proper treatment.ope