Squamous cell carcinoma of the oral cavity and circulating tumour cells

Table 1 Detection of circulating and disseminated tumour cells in oral squamous cell carcinoma and head neck squamous cell cancer

Source	Entity	n	Assay system	CTC-positive (%)	DTC-positive (%)	Clinical relevance	Number of analysed OSCC	Ref. yr of release
PB	OSCC	20	RT-PCR: CK19 mRNA	20.0		Detection of CK19-mRNA when tumour is incised	OSCC only	[85], 2000
PB	HNSCC	77	RT-PCR: CK19 mRNA	2.1		No significance for CTCs	Various sites n = 13 OSCC n = 23 oropharyngeal	[79], 2001
PB/ CVB BM	HNSCC	40	ICC: Keratins CK1-8, 10, 14-16 and 19 RT-PCR: E48 mRNA	10.0 (PCR) 20.0 (ICC)	20.0 (PCR) 32.0 (ICC)	E48 mRNA and DMFS/DFS preoperative in BM (P = 0.001/P = 0.002) and CVB (P < 0.001/P = 0.013) E48-mRNA and DMFS/DFS intraoperative in CVB (P = 0.026/0.001) ICC and DMFS preoperative in BM (P = 0.0006) and CVB (P < 0.001) ICC and DFS preoperative in BM (P = 0.036) and CVB (P = 0.042)	OSCC only	[81], 2003
BM	HNSCC	162	RT-PCR: E48 mRNA		40.0	DTC on DFS (P = 0.1460) DMFS (P = 0.2912) N > or = 2 DMFS (P = 0.0210)	Various sites n = 13 OSCC n = 23 oropharyngeal	[80], 2004
BM	HNSCC	176	ICC: CK19		30.7	OS and N-involvement (P = 0.0001), OS and DTC (0.0066)	Various sites n = 37 OSCC n = 43 oropharyngeal	[29], 2004
PB	HNSCC	21	Immunomagnetic separation: EpCAM	33.3		Occurrence of CTCs more frequent in stage III-IV than in stageI-II; connection with recurrence presumed; NS	Various sites n = 7 OSCC/ oropharyngeal	[83], 2007
PB	OSCC	25	RT-PCR: CK19 mRNA	16		Detection of CK19-mRNA when tumour is incised	OSCC only	[108], 2008
PB	HNSCC	48	Immunomagnetic separation: ICC: CK3-6H5	71		DFS and NO CTC (P = 0.01) clinical outcome and CTCs (P = 0.04)	Various sites n = 25 OSCC n = 10 oropharyngeal	[30], 2010
PB	HNSCC	42	Flow cytometry: EpCAM, CD45 RT-PCR: EGFR mRNA	43		CTC and N in flow cytometry (P = 0.014), CTC and N in RT-PCR	Various sites n = 9 OSCC n = 17 oropharyngeal	[31], 2011
PB	HNSCC	15	CellSearch™	40		CTC and M (P = 0.04)	Various sites n = 4 OSCC n =7 oropharyngeal	[84], 2012
PB	HNSCC	31	Flow cytometry: EpCAM; EGFR, CD45	29 pEGFR in 55% of CTC+-cases		Increasing number of CTC-positive cases at end of treatment	Various sites n =5 OSCC n =18 oropharyngeal	[50], 2012
PB	Under RCT HNSCC	33	Flow cytometry: EpCAM CD45 keratins 7, 8 EGFR	33 pEGFR in 36.4% of CTC+-cases		None given for comparing two methods	Various sites n = 0 OSCC (not specified) n = 13 oropharyngeal	[51], 2012
PB	HNSCC	73	CellSearch™	15.1		Decreasing CTC counts and clinical response (P = 0.017)	Various sites n = 3 OSCC n = 39 oropharyngeal	[82], 2012
BM	HNSCC	105	ICC: keratins 8, 18 and 19		14.5	No significance for DTCs (76/105 tested)	Various sites n = 72 OSCC n = 8 oropharyngeal	[68], 2012
PB BM	OSCC	110	CellSearch™ ICC: keratins 8, 18 and 19	12.5 (Cell search)	20.0 (ICC)	CTCs and T (P = 0.04), N and DTCs (P = 0.02), M and CTCs (P = 0.004), M and DTCs (P = 0.005), DTCs and RFS (P < 0.001)	OSCC only	[35], 2014

BM: Bone marrow aspirates; CD: Cluster of differentiation; CK: Cytokeratin; CTC: Circulating tumour cell; CVB: Central venous blood; DFS: Disease-free survival; DMFS: Distant metastasis free survival; EGFR: Epidermal growth factor receptor; pEGFR: Phospho-EGFR; HNSCC: Head neck squamous cell cancer; EpCAM: Epithelial cell adhesion molecule; M: Metastatic; NS: Nodal status; OS: Overall survival; OSCC: Oral squamous cell cancer; PB: Peripheral blood; RT-PCR: Reverse transcriptase-polymerase chain reaction; RFS: Relapse-free survival; T: Tumour stage; ICC: Immunocytochemistry; RCT: Randomized control trial; DTC: Disseminated tumour cells.