Feinnadelzytologie von Schilddrüsenknoten: Molekulare Diagnostik in der klinischen Routine

Abstract

Results for the detection of point mutations and rearrangements have thus far been obtained by fresh material of fine needle aspiration cytology (FNAC). After a first retrospective study we report on the diagnostic detection in routinely obtained, consecutive air-dried FNAC smears. RNA and DNA was extracted from 154 consecutive routine air-dried FNAC smears: 80 with microfollicular proliferation (MFP), 45 with follicular neoplasia (FN), 26 with the cytological diagnosis of papillary carcinomas (PTC) and 3 which were suspicious for malignancy. PAX8/PPARG and RET/PTC3 rearrangements were detected by qPCR, while BRAF and RAS point mutations were detected by pyrosequencing. Only 0.7 % and 5.3 % of the routine air-dried FNAC samples did not allow analysis of a point mutation or rearrangements, respectively. NRAS mutations could be detected in 7 MFP smears, and in one of FN and PTC samples, respectively. HRAS mutations were detected in one MPF and one FN sample. A KRAS mutation was only detected in one FN sample, whereas BRAF mutations were detected in 20 samples with PTC (but in no other sample). PAX8/PPARG was detected in 2 MFP samples, while RET/PTC was detected in only one MFP sample. In total, 13.8 % MFP-FNAC, 6.7 % FN-FNAC, and 80.8 % PTC-FNAC samples harbored a mutation. These results demonstrate that rearrangements and point mutations can be detected in routinely obtained air-dried FNAC samples.