Detection of ras mutation in fine needle aspiration cytologic specimens from neoplastic follicular nodules of the thyroid

A micromethod that allows polymerase chain reaction (PCR) amplification of proto-oncogene sequences from DNA extracted from thyroid FNA cytologic smears has been set up. A point mutation at codon 12 of H-ras gene was identified in one case, cytologically classified as follicular neoplasia and histologically diagnosed as follicular carcinoma. The method described may be useful for the preoperative identification of cancer-associated oncogenic alterations in those nodules that cannot be diagnosed at conventional light microscopy evaluation