Encouraged by these optimistic reports, we applied this method to our patients for the follow-up of DTC. However, we found that TG and TPO mRNAs were detectable in the peripheral blood of all the patients tested, a result that differs from those reported previously, and we therefore felt a need to re-evaluate TG mRNA detection. One of the problems of previous studies has been that the expressions levels of TG mRNA have not been calculated in conjunction with the use of an appropriate internal control, as the results of simple RT-PCR detection can vary in response to subtle changes in conditions.