Table 1.

Selected studies on circulating tumor cells in renal cell carcinoma patients.

Reviewed Studies	CTC Collection Method	CTC Detection Method	Patients
McKiernan et al. 1999 [16]	Density gradient centrifugation	CA9 RT-PCR	9 metastatic RCC, 28 localized RCC, 5 benign renal lesions and 54 healthy controls
Ashida et al. 2000 [3]	Density gradient centrifugation	VHL mutation-specific PCR	29 sporadic ccRCC
Allard et al. 2004 [17]	CellSearch® (EpCAM-based)	Cytokeratin expression	11 metastatic RCC, 199 benign diseases and 145 healthy controls
Li et al. 2005 [18]	Density gradient centrifugation	Cadherin-6 RT-PCR	11 metastatic RCC, 35 localized RCC and 25 healthy controls
Burzynski et al. 2005 [19]	Density gradient centrifugation	Global RT-PCR	45 advanced RCC
Bluemke et al. 2009 [20]	Density gradient centrifugation and immunomagnetic depletion of leucocytes by AutoMacs	Morphological assessment and cytokeratin expression by immunocytochemistry	154 RCC
Gradilone et al. 2011 [21]	CellSearch® (EpCAM-based)	Cytokeratin expression	25 metastatic RCC
El-Heliebi et al. 2013 [22]	ScreenCell® Cyto filtration	Morphological assessment	30 advanced RCC and 10 benign renal tumors
Nel et al. 2016 [23]	Density gradient centrifugation and hematopoietic cell depletion	Cytokeratin, N-Cadherin or CD133 expression by immunofluorescence	14 metastatic RCC and 14 healthy donors
Liu et al. 2016 [24]	NanoVelcro microfluidic platform (CA9-/CD147-capture antibodies)	Cellular diameter of 13–50 μm and positive cytokeratin expression	76 RCC, 10 benign renal tumors and 15 healthy controls
Nagaya et al. 2018 [25]	CytoQuest™ (EpCAM-based)	Cytokeratin expression without CD45 expression	1 RCC (case report)
Broncy et al. 2018 [26]	ISET® filtration	Morphological assessment and single-cell VHL-targeted PCR	2 metastatic RCC and 28 localized RCC