Classical and molecular cytogenetic analysis in head and neck squamous cell carcinomas

RESUMO

Head and neck carcinomas represent the sixth most frequent type of cancer in the world, and 90 percent are derived from squamous cells (HNSCC). In this study of 15 HNSCC cases, extensive aneuploidy was detected by G banding in most tumors. The most frequently observed numerical changes involved gain of a chromosome 22, and loss of chromosomes Y, 10, 17, and 19. The most frequent structural alteration was del(22)(q13.1). As compared to G-banding, fluorescence in situ hybridization (FISH) proved to be an effective technique for detecting aneuploidy. Interphase FISH with a chromosome 17 centromere probe disclosed a high frequency of monosomy for chromosome 17, in contrast with G-banding, by which clonal monosomy 17 was detected in only three of the tumors. Painting probes for chromosomes 5 and 16 were used to evaluate a selected series of HNSCC in which G-banding analysis had shown marker chromosomes. FISH analysis failed to confirm the origin of the marker chromosomes, but four out of five cases showed a significant loss of chromosomes 5. This difference between FISH and G-banding results may reflect the smaller number of metaphase analyzed as well as the criteria adopted for sorting these metaphases. Therefore results obtained solely by G-banding analysis should be considered with caution. Our data confirmed the involvement of chromosome 17 in head and neck squamous cell carcinomas