Background: As recurrences after treatment for differentiated thyroid
cancer can occur many years after thyroidectomy, periodic monitoring of serum
thyroglobulin (Tg) levels is performed in these patients. However, autoantibodies
that can interfere with Tg immunoassays occur in the blood of approximately 25% of
these patients. Several earlier reports suggest that measuring Tg mRNA by
reverse-transcriptase polymerase chain reaction (RT-PCR) could be of value,
especially in patients with Tg autoantibodies.
Methods: Using an earlier described, real-time quantitative Taqman
RT-PCR assay, Tg mRNA concentrations were assessed in peripheral blood taken from 58
patients treated for thyroid cancer and from two healthy controls.
Results: In all tested samples Tg mRNA could be found. No correlation
between serum Tg protein and Tg mRNA could be found. Tg mRNA concentrations did not
differ between serum Tg-negative and Tg-positive patients. No differences in the
number of patients with high or low Tg/β-actin ratios were found
between the groups of patients without, 131I uptake on whole-body scan, or
patients with thyroid bed uptake, uptake elsewhere in the neck, or distant metastases
with or without regional uptake (P = 0·871).
Conclusions: We were not able to confirm earlier positive reports on the
clinical value of Tg mRNA measurement for the monitoring of patients treated for
thyroid cancer.
