Cytogenetic characterization of low-passage cell line of follicular thyroid adenoma

Neoplasias arising from follicular thyroid cells provide a model for multistep tumorigenesis (Sozzi et al., Cancer Genet Cytogenet 1992;64:38e41). Adenomas of the thyroid are rare examples of epithelial tumors frequently displaying specific chromosomal translocations. The most commonly reported translocations involve chromosomes 2, 3, and 5 (Rippe et al., Oncogene 2003; 22:6111e4; Roque et al., Genes Chromosomes Cancer 2003;36: 292e302; Belge et al., Cancer Genet Cytogenet 1998;101: 42e8). We report the isolation and characterization of a new low-passage follicular thyroid adenoma cell line, with similar chromosomal alterations as described previously. A fresh sample was obtained from Tumour Bank of Osuna Hospital, belonging to the Tumour Banks of the Andalusia Network, from a 52year-old women diagnosed with a follicular thyroid adenoma. The sample was processed and placed in culture with specific media until growth was achieved. The culture was analyzed to determine cellular morphology, and was characterized in various phases of generation for lineage specificity by immunohistochemistry. Moreover, telomerase activity was quantified by qPCR using a telomerase repeat amplification protocol, and the DNA profile of the cell line was compared to the original tumor sample using polymorphisms in STR loci. We performed cytogenetic analysis by G-banding and spectral karyotyping. After incubation for a few weeks, cells grew as a firm adherent monolayer with spindle-epithelial like morphology, and formed piled-up cell colonies. The epithelial nature of the cultured cells was confirmed by immunocytochemical analysis using an anti-cytokeratin cocktail. Telomerase activity was positive and the cells showed a single DNA profile, concordant with the tumor origin of the sample. Cytogenetic analysis, in middle passage, showed a modal chromosome number of 44e45 with three clonal rearrangements: an unbalanced translocation between chromosomes 2 and 3 [t(2;3) (q32;?)], between chromosomes 2 and 10 [(t(2;10)(q24;?)] and a derivative marker chromosome from 5 and 13 [t(5;13) (?;p11.2)]. Furthermore, we observed a deletion of chromosome 13 (13q21) and a monosomy of chromosomes 3 and X in all analyzed metaphases. These results indicate that the features of this cell line are similar to follicular thyroid adenomas described by others and, therefore, offer researchers a good tool for cancer investigation. RECURRENT COPY NUMBER ALTERATIONS IN ESOPHAGEAL SQUAMOUS CELL CARCINOMAS