Division of Pediatrics, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA.
BACKGROUND: In patients with neuroblastoma morphological assessment of BM for residual NB cells is not precise, particularly when the number of tumor cells is small. PROCEDURE: To develop a sensitive and rapid method of detecting NB cells in BM, we assessed the efficiency of flow cytometry (FCM) using markers CD9, CD56, and CD45. The percent of CD9+/CD56+/CD45- (NB phenotype) cells was determined by FCM in 41 samples (16 patients) at various time points. For confirmation fluorescence in situ hybridization (FISH) for 17q gain was performed. RESULTS: Nineteen of the 22 (86%) samples that were negative by morphology were positive by FCM (>0.006% CD9+/CD56+/CD45- cells). The longest time to complete the FCM study was 3 hr. In six FISH experiments the sorted CD9+/CD56+/CD45- population had a higher percentage of cells with 17q gain (11.5-95%) compared to a CD56-/CD45+ internal control population (2-8%). CONCLUSIONS: Our preliminary results suggest that FCM determination of the percent of CD9+/CD56+/CD45- cells is an effective method of rapidly detecting NB cells in BM. (c) 2005 Wiley-Liss, Inc.