Pancreatic cancer: Are "liquid biopsies" ready for prime-time?

Table 1 Studies reporting detection of circulating tumour cells in patients with pancreatic cancer

Study	CTC platform	Markers	Stage of disease	Time of sampling	Number of patients, n	Cut-off for positivity per 7. 5 mL blood	CTCs detected, n
Zhang et al[16] 2014	Immunocy-togenetics	CK, CD45, DAPI, CEP8	All stages	Pre-operative	22	4	16/22 (72.7%)
Rhim et al[17] 2014	Micro-fluidic "GEM" Chip	DAPI, CD45, CK, PDX-1	All stages	Diagnosis	11	≥ 1	8/11 (73%)
Khoja et al[12] 2011	CellSearch and ISET	EpCAM, CK, vimentin, E-cadherin	All stages	Diagnosis or at time of diagnosis of progressive disease > 6 wk from therapy	53	≥ 1	21/53 (40%) using CellSearch
							24/27 (93%) using ISET
Nagrath et al[18] 2013	CTC-Chip	Cks	Metastatic	Not stated	15	37.5 (5/mL)	15/15 (100%)
Allard et al[15] 2004	CellSearch	CK8, CK18, CK19	Metastatic	Not stated	16	≥ 1	6/16 ((38%)
Gall et al[19] 2013	CellSearch	EpCam, EGFR	Locally advanced	Pre-treatment	75	≥ 1	4/75 (5%)
Ren et al[20] 2011	Immuno-cyto-chemistry	CA 19-9, CK8, CK18	Locally advanced and metastatic	Pre- and post- treatment	41	≥ 1	33/41 (80.5%) pre-treatment and 12/41 (29.3%) post-treatment

CTC: Circulating tumour cell.