Table I.

Details of included studies.

Authors, country, year of publication	Number of patients	Subject studied	Conclusion/Results
Ghossein RA et al., USA, 1999 [21]	N/A*	Detection of circulating tumor cells and micrometastasis with PCR technique	Utility in melanoma. Discrepancies in thyroid carcinoma
Theresia W et al., Germany, 2003 [20]	19	Detection of CK20-, GRP-mRNA in circulating tumor cells from medullary thyroid carcinoma by RT-PCR technique	CK20-mRNA, GRP-mRNA useful for diagnosis of hematogenic and lymphogenic dissemintion
Takashi S et al., Japan, 2005 [19]	121	Detection of circulating tumor cells by RT-PCR for CEA-mRNA with the purpose to distinguishing follicular carcinoma by adenoma	CEA-mRNA determination is useful for distinguishing follicular carcinoma by adenoma. Sp=100%, Se=46%
Su-Ynn C et al., USA, 2006 [4]	258	TSHR-mRNA measurement role in the preoperative diagnosis of thyroid cancer	Se=93% in recurrence of thyroid carcinoma, a good alternative to serumTg
Gupta M, Chia SY, USA, 2007 [22]	N/A*	Circulating thyroid cancer markers evaluation	TSHR-mRNA count in patients with indeterminate FNAB can improve cancer detection
Tomislav N et al., USA, 2009 [18]	510	Determination of circulating cancer cells in patients with thyroid microcarcinoma	TSHR-mRNA presence in the CTC’s a high susceptibility of metastasis or aggressiveness
Winkens T et al., Germany, 2013 [14]	162	CEC determination helped by EpCAM, as a potential marker of thyroid malignant cancer dissemination	CEC’s were found at a high level in patients with DTC than in healthy volunteers
Winkens T et al., Germany, 2014 [13]	28	RIT influence on the CEC’s number in patients with differentiated thyroid carcinoma	It was observed a low number of CTC’s after RIT and also a high level of sTg
Sorg S et al., Germany, 2014 [17]	5	Determining tissue origin of CEC in patients with thyroid carcinoma by RT-PCR technique	33% of CEC originate from thyroid tumor

N/A* - not available