Table 2.

Overview of published studies with in vitro CTC cultivation.

Cancer type	Isolation method	Efficiency	Cultivation conditions			Tumorigenicity	References	Notes
			Hypoxia	Non-adherent/adherent	2D/3D
Breast cancer	CTC-iChip	6/36	Hypoxia	Non-adherent	Tumoroids	3/6 tumorigenic	[70]
Breast cancer	RosetteSep™	1/50	Standard	Mixed	2D	Tumorigenic	[71]
Breast cancer	Ficol-Paque density gradient	12/12	NS	Attached to leukocyte layer	–	NA	[72]	CD45+ leukocytes included in culture
Breast cancer	RosetteSep™ CTC enrichment cocktail containing anti-CD56	36/48	Hypoxia for 1 week, then standard	Non-adherent	–	NA	[97]	Nanoemulsions in culture media
Breast cancer	Ficoll-Hypaque gradient centrifugation	1/16	–	Adherent	2D	Tumorigenic	[74]	0/16 bowel cancer, 0/18 stomach cancer
Non-small cell lung cancer	Microfluidic Herringbone-Chip and EpCAM-coated and EGFR-coated immunomagnetic microbeads	2/89	Hypoxia followed by standard	Non-adherent followed by adherent	2D	Tumorigenic	[82]	Only 1 maintained more than 6 months in culture
Non-small cell lung cancer	RosetteSep™ Human CD45 depletion cocktail	9/70	Hypoxia	Adherent	2D	NA	[98]	Short-term culture (40 days)
Small cell lung cancer	Density gradient centrifugation	3/30	Standard	Adherent	2D	NA	[79]
Small cell lung cancer	RosetteSep™ CTC enrichment cocktail	18/22	Standard	Adherent	Spheroids	NA	[81]	Cultivation on binary colloidal crystals
Early-stage lung cancer	CTC-capture microchip with EpCAM-based detection	14/19	Standard	–	3D	NA	[84]	Coculture with CAF on collagen/matrigel
Colorectal cancer	Density centrifugation with negative selection form CD45	1/4	Standard	–	Tumoroids	NA	[110]	CTC isolated from PDX mouse model
Colon cancer	RosetteSep™ human circulating epithelial tumor cell enrichment cocktail	2/71	Hypoxia followed by standard	Non-adherent	Spheroids	Tumorigenic	[86]	CTC count of ≥300.
Metastatic colorectal cancer	RosetteSep™ human circulating epithelial tumor cell enrichment cocktail	3/35	Standard	Suspension	Spheroids	Tumorigenic	[88]	Successful establishment only from stage IV patients without neo-adjuvant therapy
Pancreatic cancer	Size-based microfluidic CTC isolation with labyrinth	3/10	Standard	Adherent	Spheroids	Tumorigenic	[90]	Originally adherent cultures on fibronectin-coated surface, followed by cultivation as non-adherent spheroids
Pancreatic cancer	RosetteSep™ CTC enrichment cocktail kit	36/41	–	–	Tumoroids	NA	[91]	Cells seeded onto a binary colloidal crystal substrate containing silica and polymethyl methacrylate
Prostate cancer	RosetteSep™ human CD45 depletion cocktail	1/17	Standard	–	Organoids		[77]	CTC count more than 100/8 ml blood
Prostate cancer	Diagnostic leukapheresis + RosetteSep™ Human CD45 depletion cocktail	14/40	Standard	–	Tumoroids	NA	[78]	6–8 weeks is culture until proliferation stalled, 2 cultures more than 6 months, 1 culture gave rise to stable cell line
Endometrial, prostate, ovarian, gastric cancer	MetaCell® filtration	Various	Standard	Adherent on filter	–	NA	[111–114]	Short-term (2 weekS) and long-term (6 months) efficiency of CTC capture 52% PCa, 75% endometrial, 59% gastric, 65% ovarian
Gastroesophageal cancer	RosetteSep™ CTC enrichment cocktail with anti-CD36	2/23	Hypoxia	Adherent/non-attached	–	Tumorigenic	[115]	Long-term culture over 1 year
Lung, colon, pancreatic cancer	Ficol-Paque density gradient	5/5 lung 5/7 colon 13/13 pancreas		Adherent		Tumorigenic	[73]	Short-term culture, CTCs attached to CD45+ cells

Summary of the main characteristics of studies describing short- or long-term in vitro culture of CTCs.

CAF cancer-associated fibroblasts, NA not analyzed, NS not specified.