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Background:The accurate diagnosis of thyroid tumors is challenging. Proteomics has emerged as a promising approach for the discovery of molecular diagnostic markers as a potential complement to routine diagnostics.Methods:Protein fractions from 29 frozen thyroid tumor tissue samples (10 papillary carcinomas, 9 follicular carcinomas, and 10 follicular adenomas) as well as from normal thyroid tissue were analyzed by surface enhanced laser desorption/ionization time-of-flight mass spectrometry followed by validation by Western blotting and immunohistochemistry.Results:A Ca2+-binding protein belonging to the S100 family, S100A6, was differentially expressed between papillary and follicular thyroid tumors. Moreover, two posttranslationally modified forms of S100A6 were observed and verified by liquid chromatography-coupled tandem mass spectrometry. Validation by Western blotting displayed a significantly higher expression of S100A6 in papillary thyroid carcinoma (PTC) in comparison with the other tumor groups or normal tissue (p< 0.05). Immunohistochemical analysis on 98 tumors showed that PTC cases had a significantly stronger cytosolic staining and a larger proportion of stained nuclei than follicular tumors. BRAFgene mutation was not significantly associated with S100A6 protein levels.Conclusion:This study supports a role of S100A6 in thyroid tumorigenesis and as a potential aid in the discrimination between follicular thyroid tumors and PTC. [ABSTRACT FROM AUTHOR]

In this study we present two novel anaplastic thyroid carcinoma (ATC) lines (HTh 104 and HTh 112) and further characterize six frequently used ATC lines (HTh 7, HTh 74, HTh 83, C 643, KAT-4, and SW 1736). Three of the lines carried a heterozygous BRAFmutation V600E, which is in line with reports of BRAFmutations in primary ATC and papillary thyroid cancer. Several nonrandom breakpoints were identified by spectral karyotyping (SKY) and G-banding in these lines including the novel 1p36 and 17q24-25 as well as 3p21-22 and 15q26 that are also implicated in well-differentiated thyroid cancers. Comparative genomic hybridization showed frequent gain of 20q, including the UBCH10gene in 20q13.12, which was further confirmed by array-comparative genomic hybridization and fluorescence in situhybridization analyses. Our results concur with previous studies in both primary tumors and cell lines, indicating that gain of chromosome 20 is important in the pathogenesis of ATC and/or progression of differentiated thyroid cancers to ATC. [ABSTRACT FROM AUTHOR]