Table 1.

Clinical significance of CTCs in colorectal cancers.

Number of Patients	Detection Method	CTC No. (%)	Clinical Significance	Ref.
34	Multiplex PCR	20 (59)	Therapy alignment and monitoring; CTCs could predict chemotherapy response; moreover, EGFR status of CTCs could predict the likelihood of targeted therapy response.	[48]
30	Density gradient centrifugation, CK20 qRT-PCR and immunomagnetic CTC number determination	30 (100)	CTC number reflects the chemotherapeutic sensitivity of CRC patients. Microscopic CTC single-cell, doublet, and cluster numbers were found in correlation with CK20 qRT-PCR results.	[49]
40	CELLection Dynabeads®	27 (68)	Therapy alignment and monitoring. Significant shorter progression-free survival (PFS) was found in patients with CTCs positive for the expression of ALDH1, survivin and MRP5.	[50]
467	CellSearch	467 (100)	Therapy alignment and monitoring; CTC count provides additional information to CT imaging for early recurrence monitoring.	[51]
141	RT-PCR	141 (100)	Therapy alignment and monitoring; CTC persistence after surgical resection was a significant marker for early recurrence.	[52]
14	CellSearch	14; 4 (29) after chemotherapy	Therapy alignment and monitoring; CTC-negative patients after chemotherapy had significantly better treatment response.	[53]
42	CellSearch	22 (52.3)	Patients with CTCs ≥3/7.5 mL may benefit from the intensive 4-drug regimen (irinotecan, oxaliplatin, and tegafur-uracil with leucovorin and cetuximab).	[54]
61	CellSearch	27 (44.3)	CTC heterozygosity and heterogeneity exist in KRAS status among CTCs within all patients and between CTCs and tumor tissues.	[55]
66	CanPatrol Multiplex mRNA-ISH	57 (86.4)	CTC count ≥6/5 mL was associated with decreased PFS and OS. LGR5 expression in CTCs may serve as a marker for CRC metastasis.	[56]
138	ISET device-CTCBIOPSY	63 (45.7)	Postcurative resection CTC count > 1/2.5 mL was associated with shorter 3-year RFS rate.	[57]
91	CanPatrol mRNA-ISH	51 CTC (56.0); 46 mCTC (50.5)	Mesenchymal CTC count ≥1/5 mL and COX-2 expression in mCTCs were associated with distance metastasis.	[58]
34	Microfluidic chips	34 (100)	Therapy alignment and monitoring; comparison of mutational status of CTCs, ctDNA, and primary tumor tissue revealed great heterogeneity.	[59]
130	MACS	67 (51.54)	Postoperative CTC count ≥2/3.2 mL in non-mCRC was associated with decreased RFS.	[60]
106	MACS	100 (94)	HAI/target therapy with drugs selected by liquid biopsy precision oncotherapy is a safe and efficacious alternative therapeutic strategy for unresectable colorectal liver metastases patients.	[61]
21	ScreenCell®	21 (100)	Isolation of CTCs by size (as a label-free technique with subsequent immunofluorescence labeling) gives a very high detection rate.	[62]
21	CK20 RT-qPCR	15 (71.4)	The CK20 RT-qPCR method gives a relatively high detection rate.	[62]
21	NYONE®	11 (52.4)	Application of a semiautomated microscopic approach with NYONE®, an examiner-independent procedure for CTC detection.	[62]
50	CellSearch	46 (92)	CTC counts ≥3/7.5 mL at baseline and day 21 after initiation of regorafenib were associated with decreased PFS and OS. Patients had significantly increased EGFR expression at day 21 and/or PD compared to baseline.	[63]
589	CellSearch	241 (41)	Baseline CTC counts ≥3/7.5 mL were associated with clinical or pathologic features associated with poor prognosis.	[64]
7	ScreenCell®, Immunofluorescence Staining	7 (100)	Promising test for the future isolation and characterization of different CTC subtypes, including clusters.	[65]