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Laser capture microdissection is a valuable tool in the preoperative molecular screening of follicular lesions of the thyroid: an institutional experience

2014; Wiley; Volume: 26; Issue: 5 Linguagem: Inglês

10.1111/cyt.12226

1365-2303

Massimo Bongiovanni, Francesca Molinari, Markus Eszlinger, Ralf Paschke, Jessica Barizzi, Elisabetta Merlo, Luca Giovanella, Fabrizio Fasolini, Fabio Cattaneo, F Ramelli, Luca Mazzucchelli, Milo Frattini,

Genetic factors in colorectal cancer

Objectives The application of molecular tests to thyroid fine needle aspiration ( FNA ) has been shown to be a valuable tool to better refine the pre‐operative malignant risk of patients with indeterminate cytology results. In this study, we investigated the feasibility of using the laser capture microdissection ( LCM ) technique to obtain DNA and RNA for molecular tests in routine thyroid FNA smears. Methods Nine coupled FNA and histological retrospective cases and 31 prospective FNA cases with a follicular neoplasm/suspicious for a follicular neoplasm ( FN / SFN ) diagnosis were included in this study. Both cytological and histological specimens were investigated by direct sequencing and reverse transcription‐polymerase chain reaction ( RT ‐ PCR ) for BRAF and RAS mutations and for PAX 8/ PPARG and RET / PTC rearrangements, respectively. Results LCM yielded good DNA and RNA quality in all cases (100%) in both series, irrespective of the staining used (Giemsa, Papanicolaou, immunostain for thyroglobulin) and the cytology technique (conventional or liquid‐based preparations). Total mutations found in the FNA and in the corresponding histological specimen in both series were: one PAX 8/ PPARG rearrangement in a follicular carcinoma ( FC ), four NRAS mutations [in two FC s, one papillary carcinoma and one follicular adenoma ( FA )] and one HRAS mutation in one FA . The sensitivity was 67% and the specificity was 91%. Conclusions LCM is a valuable tool to obtain good quality DNA and RNA for molecular tests in cytological material from thyroid FNA , and can be a useful option in the management of patients with an FN / SFN FNA diagnosis.