[Aspiration biopsy RNA diagnosis]

Recent advances in molecular-based techniques, especially RNA analyses such as differential display, serial analysis of gene expression(SAGE) and DNA arrays, have enabled us to detect the specific changes in mRNA in cancer tissues rapidly and easily. We have established a new method of preoperative molecular-based diagnosis of thyroid carcinomas, one of the most common cancers in females. This technique, Aspiration Biopsy RNA Diagnosis, ABRD, allows us to perform preoperative RNA analysis of the tumors by extracting RNA from tumor cells obtained by fine needle aspiration biopsies(FNABs). For example, by ABRD detection of oncofetal fibronectin or calcitonin mRNA in FNABs, three types of thyroid carcinomas, papillary, anaplastic and medullary carcinomas, were accurately diagnosed preoperatively without the help of cytological or pathological examinations by a skillful pathologist. Further, by real-time monitoring RT-PCR measuring the expression levels of these cancer-specific mRNAs, a fully automated system was established. Because ABRD can be performed without any severe invasion to the patients, in the near future, when more reliable systems of quantitative RNA analysis are developed, ABRD will probably become one of the standard tests for preoperative diagnosis of cancer.