Circulating and stool nucleic acid analysis for colorectal cancer diagnosis

Table 1 Summary of studies that have tested DNA integrity and genetic alteration markers in blood samples in colorectal cancer

Study	Biomarker(s)	Methods	Case analyzed	Main results
Flamini et al[17], 2006	Serum cfDNACEAcfDNA and CEA	qRT PCR	CRC: 75HD: 75	Sensitivity	Specificity
				81%	73%
				39%	97%
				88%	71%
Frattini et al[51], 2006	Plasma cfDNA	DNA Dipstick Kit	CRC: 70HD: 20	CRC (T0) mean value DNA: 495.7 ng/mL
				CRC (FU at 4 mo) mean value DNA: 170.6 ng/mL
				CRC (FU at 10 mo) mean value DNA: 240.9 ng/mL
				CRC (FU at 10 mo)(DFP) mean value DNA: 136.2 ng/mL
				CRC (FU at 10 mo)(RP) mean value DNA: 694.4 ng/mL
				HD: mean value DNA 10.3 ng/mL
				Altered in only 37% of CRC patients
Umetani et al[61], 2006	Plasma cfDNASerum cfDNA	ALU qRT PCR	Breast, Colorectal, Thyroid Cancer: 22Thyroid A: 2	Mean ± SD value plasma cfDNA: 180 ± 150 pg/μL
				Mean ± SD value serum cfDNA: 970 ± 730 pg/μL
Umetani et al[64], 2006	Absolute serum DNAIntegrity serum DNA Alu repeats (2 sites)	ALU qRT PCR	CRC: 32HD: 51	CRC (I-II) mean absolute value DNA: 1.63 ng/μL
				CRC (I-II) mean integrity DNA: 0.22 ng/μL
				CRC (III-IV) mean absolute DNA: 1.73 ng/μL
				CRC (III-IV) mean integrity DNA: 0.22 ng/μL
Boni et al[52], 2007	Plasma cfDNACEA	qRT PCR	CRC: 67HD: 67	CRC: Mean value DNA 57.93 ng/mL
				HD: Mean value DNA 0.85 ng/mL
				Evaluated in only 47% of patients
Danese et al[65], 2010	Serum cfDNACEA	RT-PCR	CRC: 118P: 49HD: 26	Sensitivity	Specificity
				83%	92%
				36%	100%
Mead et al[31], 2011	Plasma cfDNA (4 DNA markers) CEA	PCRELISA	CRC: 24P: 26HD: 35	AUC: cfDNA: 0.81
				AUC (CEA and cfDNA): 0.855
				P: Sensitivity: 83%; Specificity 72%
Czeiger et al[66], 2011	Serum cfDNA	Fluorometric Assay	CRC: 38HD: 34	Sensitivity	Specificity
				42%	94%
da Silva Filho et al[67], 2013	Serum cfDNAAlu repeats (2 sites)	qPCR	CRC not operated on: 27CRC operated on: 33HD: 30	CRC not operated on: 0.08-62.10 pg/μL
				CRC operated on: 0.01-186.7 pg/μL
				HD: 0.01-26.11 pg/μL
				Mean value range (according to different Alu analysis)

cfDNA: Cell-free circulating DNA; HD: Healthy donors; A: Adenomas; P: Polyps; T₀: Time 0; FU: Follow up; DFP: Disease free patients; RP: Recurrence patients; AUC: Area under the receiver-operating characteristic (ROC) curve; qRT PCR: Quantitative real time polymerase chain reaction; ELISA: Enzyme-linked immunosorbent assay.