Detection of CD44 variants in fine needle aspiration biopsies of thyroid tumor by RT-PCR

Increased expression of CD44 variants is often observed in differentiated thyroid carcinomas. To establish a method for gene diagnosis of thyroid without any additional invasions to the patients, RNA in leftover cells inside the needle used for fine needle aspiration biopsies (FNABs) was extracted to detect the expression of CD44 variants by reverse transcription-polymerase chain reaction (RT-PCR). After FNAB and preparation of sample on a slide glass for cytological examinations, RNA in leftover cells inside the needle was extracted. After reverse transcription, cDNA was amplified by PCR with specific primers for CD44. The results were compared with the cytological diagnosis. CD44 variants were detectable in all seven samples that were diagnosed as positive cytology. However, they were detected in only five of the 29 samples of negative cytology. Therefore, thyroid tumors may be more accurately diagnosed by a combination of cytological examination and detection of CD44 variants in RNA obtained by FNAB.