Table 2.

Studies reporting detection of circulating tumour DNA in patients with pancreatic cancer

Study	CtDNA platform	Markers	Stage of disease	Time of sampling	Number of patients, n	Markers detected, n
Zhou et al[32] 2011	Nested RT-PCR	H-tert, C-MET, CK20, CEA mRNAs	All stages	Pre-treatment	25	H-TERT 25/25 (100%)
						CMET 20/25(80%), CK20 21/25 (84%), CEA 20/25 (80%)
de Albuquerque et al[22] 2012	Immunomagnetic RT-PCR	KRT19, MUC1, EpCAM, CEACAM5, BIRC5	Stage III and IV	Pre-treatment	34	16/34 (47%)
Chausovsky et al[33] 1999	RT-PCR	CK20	Metastatic	Not stated	28	22/28 (79%)
Sausen et al[28] 2015	Digital PCR	KRAS	Localised	Pre-treatment	51	22/51 (43%)
Earl et al[27] 2015	Digital PCR	KRAS	All stages	Pre-treatment (NB 7 patients had received chemotherapy)	31	8/31 (26%)
Sergeant et al[31] 2011	RT-PCR	EpCAM	Stage I,II and 4	Pre and post treatment	40	10/40 (25%) preoperatively,
						10/35(28.6%) D1, 9/39 (23.1%) at D7, 8/34 (23.5%) at 6 wk
Bettegowda et al[26] 2014	Digital PCR	KRAS, NRAS, PIK3CA, BRAF	Localised and metastatic	Not stated	155	48% of those with localised and > 80% metastatic disease
Zill et al[30] 2015	NGS	KRAS, TP53, APC, SMAD4, FBXW7	Localised and metastatic	Post-treatment	17	17/17 (100%)
Kinugasa et al[29] 2015	Digital PCR	KRAS	All stages	Pre-treatment	75	47/75 (62%)

CtDNA: Circulating tumour DNA; RT-PCR: Reverse transcription polymerase chain reaction.