[Molecular-based diagnosis of thyroid carcinomas by detecting cancer-specific mRNAs]

Molecular-based diagnosis of thyroid carcinomas can be more easily established by utilizing specific mRNAs that are restrictedly expressed in cancer tissues. In light of this aspect, we searched for cancer-specific mRNAs using sequence specific-differential display(SS-DD) and serial analysis of gene expression(SAGE). By these techniques, we found several mRNAs that efficiently distinguished benign and malignant tissues. Among these, oncofetal fibronectin(onfFN) mRNA was expressed only in thyroid papillary and anaplastic carcinomas and it was considered the most preferable target for molecular-based diagnosis of these carcinomas. In a previous study, we introduced a new method of preoperative diagnosing thyroid carcinomas. This technique, aspiration biopsy-RT-PCR(ABRP), allows us to simultaneously perform cytological and molecular-based diagnoses by extracting RNA from leftover cells within the needle used for fine needle aspiration biopsies(FNABs). ABRP provides both RNA information and cytological diagnosis without further invasion to the patient. We demonstrated that by ABRP detection of onfFN mRNA in FNABs, papillary and anaplastic carcinomas may be accurately diagnosed preoperatively. Further, by real-time monitoring RT-PCR measurement of onfFN mRNA, a fully automated system was established.