Molecular cytogenetic characterization of primary cultures and established cell lines from non-medullary thyroid tumors

To further delineate the role of chromosomal aberrations in non-medullary thyroid tumors, we performed cytogenetic analyses of established thyroid cancer cell lines and primary tumors using spectral karyotyping (SKY), G-banding and comparative genomic hybridization (CGH). Five of the primary thyroid tumors revealed an abnormal karyotype. In a follicular thyroid carcinoma, we observed two translocations t(2;10), t(2;5) and losses of chromosomes 10p and 22. In a papillary thyroid carcinoma (PTC), a balanced translocation t(3;15) was revealed, while a case of metastatic PTC carried several clonal translocations involving ten different chromosomes. Numerical aberrations were observed in two of the five follicular adenomas analyzed, both leading to gain of chromosome 7 material. Furthermore, we cytogenetically characterized the three established thyroid cancer cell lines CGTH W-1, ARO and DRO. SKY, in combination with G-banding, revealed structural and numerical karyotypic abnormalities in all three cell lines and the breakpoint regions partly overlapped those of the primary tumors. The copy number changes detected by CGH correlated well with the karyotypic findings and demonstrated high-level amplifications in chromosomes 1, 5, 7, 8, 9, 11 and 19. The results provide evidence of chromosomal regions involved in non-medullary thyroid tumorigenesis, while further characterization of the observed translocations may lead to the identification of novel fusion oncogenes for thyroid cancer.