Structural and numerical aberrations of chromosome 22 in a case of follicular variant of papillary thyroid carcinoma revealed by conventional and molecular cytogenetics

This study reports a case of papillary carcinoma with vesicular components showing multiclonal aberrations of chromosome 22 as revealed by RHG-banding cytogenetics and by fluorescence in situ hybridization (FISH; whole chromo some 22 and BCR-ABL-specific locus probes, multi-FISH). Four clones with ch romosome 22 changes as the sole abnormality were seen. The main abnormal cl one lacked the whole chromosome 22. A del(22)(q11) was observed in a second group of cells. The third clone had an idic(22). Finally, FISH revealed a fourth abnormal cell population with a der(17)t(?17;22). Some of these chro mosome 22 alterations have been described in other solid tumors such as men ingiomas and neurinomas, suggesting a common genetic pathway of tumor progr ession occurring in a multistep process. Chromosome 22 changes do not seem to be involved in pure papillary thyroid tumors and therefore could be rela ted to the maintenance of a follicular-type histological pattern. (C) 2000 Elsevier Science Inc. All rights reserved.