The use of TPO mRNA in the detection of thyroid carcinomas has also been reported in conjunction with some studies. However, our preliminary data showed that TPO mRNA was detectable by RT-PCR in all the samples tested, including those from healthy subjects and patients after total thyroidectomy without distant metastasis (data not shown). Considering that TPO mRNA are usually less abundant than TG mRNA in thyroid cells, it is not likely that the use of TPO mRNA instead of TG would improve the clinical usefulness of this method.