Blood thyroglobulin and TSH receptor mRNA detection by RT-PCR in the follow-up of differentiated thyroid cancer patients.
OBJECTIVE
During the last years several groups have used the technique of RT-PCR for the detection of circulating thyroid cells, through the amplification of thyroglobulin (Tg) and TSH receptor(TSH-R) mRNA; however the published results are controversial. In this study we investigated the utility for the detection of Tg and TSH-R mRNA by RT-PCR in patients with differentiated thyroid cancer (DTC) during treatment with levothyroxine.


METHODS
We investigated the expression of Tg and TSH-R mRNA by single and nested RT-PCR in the blood of 3 groups of subjects: (A) 34 patients with DTC and no evidence of disease, (B) 8 patients with DTC and evidence of local or distant metastasis and (C) 13 normal subjects. Expression levels of Tg mRNA were also analysed by comparative semi-quantitative RT-PCR.


RESULTS
Tg and TSH-R mRNA signals were detected in all subjects (patients with DTC with and without evidence of disease and in normal subjects) by single or nested RT-PCR. By semi-quantitative RT-PCR and densitometric analysis of PCR products, mean levels of circulating Tg mRNA of the 3 groups were: Group A 0.182+/-0.107, Group B 0.329+/-0.298 and Group C 0.305+/-0.217.


CONCLUSIONS
Single or nested RT-PCR for Tg and TSH-R mRNA is not a suitable tool in the follow-up of patients with DTC. Lower levels of Tg mRNA in patients with DTC without evidence of disease, although not significant, may indicate that small numbers of thyroid cells may be normally present in the circulation or may represent an ectopic transcription of messengers from blood cells.
Torosian
L
L
Departamento Básico de Medicina, Hospital de Clínicas, Facultad de Medicina, Montevideo, Uruguay. torosian@hc.edu.uy
Manrique
G
G
Alvarez
B
B
Lago
G
G
Roca
R
R
Belzarena
C
C
D018263:Adenocarcinoma, Follicular / Q000097:blood* / Q000473:pathology / Q000532:radiotherapy / Q000601:surgery; D014408:Biomarkers, Tumor / Q000097:blood*; D002291:Carcinoma, Papillary / Q000097:blood* / Q000473:pathology / Q000532:radiotherapy / Q000601:surgery; D002454:Cell Differentiation; D003131:Combined Modality Therapy; D005189:False Positive Reactions; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use; D008297:Male; D009360:Neoplastic Cells, Circulating; D011237:Predictive Value of Tests; D012333:RNA, Messenger / Q000097:blood*; D012334:RNA, Neoplasm / Q000097:blood*; D019275:Radiopharmaceuticals / Q000627:therapeutic use; D011989:Receptors, Thyrotropin / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity; D013954:Thyroglobulin / Q000235:genetics*; D013964:Thyroid Neoplasms / Q000097:blood* / Q000473:pathology / Q000532:radiotherapy / Q000601:surgery; D013965:Thyroidectomy
D014408:Biomarkers, Tumor; D007457:Iodine Radioisotopes; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D019275:Radiopharmaceuticals; D011989:Receptors, Thyrotropin; D013954:Thyroglobulin