Background: The utility of fine-needle aspiration (FNA) material in the molecular characterization of a group of neuroblastic tumors (NT) in children is presented.
Methods: A recent study showed a high accuracy rate for FNA cytology (FNAC) in combination with immunostaining as a diagnostic method in 26 children with NT. In the current study FNA smears from 18 children were analyzed, either at the time of diagnosis or retrospectively, on available stored smears for cellular DNA content (DNA ploidy) by means of image cytometry (ICM) and 1p deletion and N-myc amplification by interphase fluorescent in situ hybridization (FISH).
Results: A total 62 analyses (DNA ploidy, 20 analyses; chromosome 1 or 2 number, 11 analyses; 1p deletion, 16 analyses; and N-myc, 15 analyses) resulted in clear information in 60 cases, whereas 2 tests for N-myc amplification failed. The results were compared with each other and with cytometric DNA analyses on tumor touch imprints (n = 12) and N-myc analyses on material from surgical specimens (Southern blot analysis, n = 12). The results were concordant in all but seven analyses (all with clear informative results) in six children. These discrepancies may be explained as an effect of either chemotherapy or tumor heterogeneity.
Conclusions: FNA is a fast and noninvasive diagnostic technique that yields sufficient material for the molecular characterization of neuroblastic tumors by means of FISH and ICM. Such analyses are of prognostic significance because they predict tumor behavior and response to therapy according to International Neuroblastoma Staging System/International Neuroblastoma Risk Groups criteria. In the majority of cases it also is possible to obtain material for storage and future investigations.