Objective: To characterize the cytogenetic alterations of esthesioneuroblastoma (ENB).
Methods: Comparative genomic hybridization (CGH) was performed on genomic DNA extracted from 12 patients with primary ENB, 4 patients with tumor recurrence and 7 with metastasis. Equal amounts of biotin-labeled tumor DNA and digoxigenin-labeled normal reference DNA were hybridized to normal meta phase chromosomes. Tumor DNA was visualized by fluorescein (FITC) and normal DNA by rhodamin (TRITC ) and detected by fluorescence microscopy. The signal intensities of the different fluorochromes were quantitated as gray levels along the single chromosomes. The over-and under-represented DNA segments were determined by computation of FITC/TRITC ratio images and average ratio profiles.
Results: Consensus deletion regions were most frequently observed on chromosomes 1p, 2q, 3p/q, 4p/q, 5p/q, 6q, 8p/q, 9p, 10p/q, 11p, 12q, 13q, 18q, and 21q. DNA over-representations were identified on chromosomes 1p, 7q, 9q, 11q, 14q, 16p/q, 17p/q, 19p/q, 20p/q and 22p/q. The genetic pattern of ENB was distinct from that of other small round-cell tumor types and neuroblastomas. The deletion on chromosome band 1p21-p31 was associated with bad prognosis. In particular, all patients died whose tumors had combined 1p21-p31 deletion, with tumors in clinical stage C or D, and of low differentiation (grade III or IV). Clonality analysis revealed a high concordance between pairs of primaries and metastases.
Conclusion: CGH analysis identifies characteristic cytogenetic aberrations of esthesioneuroblastoma associated with its malignant phenotype.