Table 1.

Association between the cell-free DNA level, methylation status of SFRP1, SFPR2, SDC2, and PRIMA1 in the plasma of colorectal adenoma and cancer patients and their clinicopathological parameters

				Methylation rate (mean ± SD)
		CfDNA level (mean ± SD)		SFRP1					SFRP2		SDC2		PRIMA1
Variables	n (%)	Cell-free DNA amount (ng)	P-value	Methylation (%)		P-value		Methylation (%)		P-value	Methylation (%)	P-value	Methylation (%)	P-value
Colorectal adenoma
Size			0.18			0.35				0.38		0.77		0.99
≤ 1 cm	18 (48.6)	66.43 ± 46.92		4.36 ± 10.66					0.32 ± 0.54		3.05 ± 7.31		4.88 ± 6.38
>1cm	19 (51.4)	50.07 ± 21.14		2.68 ± 5.30					0.70 ± 1.10		1.43 ± 0.54		4.58 ± 6.60
Number			0.05			0.84				0.88		0.91		0.37
1	15 (40.5)	44.14 ± 19.51		2.19 ± 3.66					0.65 ± 1.12		2.66 ± 7.67		4.13 ± 7.19
≥ 2	22 (59.5)	67.5 ± 42.39		4.39 ± 10.31					0.42 ± 0.68		1.92 ± 3.31		5.13 ± 5.95
Histological classification			0.57			0.49				0.79		0.42		0.39
Tubular	20 (54.1)	56.01 ± 36.9		5.16 ± 11.00					0.43 ± 0.73		2.74 ± 6.97		6.06 ± 7.97
Tubulovillous	14 (37.8)	60.68 ± 36.98		1.34 ± 1.62					0.54 ± 0.96		1.91 ± 3.00		2.87 ± 3.76
Hyperplastic	3 (8.1)	58.71 ± 28.59		2.48 ± 1.70					0.93 ± 1.58		0.12 ± 0.11		4.5 ± 0.70
Colorectal cancer
DUKES stages			0.77			0.14				0.96		0.85		0.13
A-B	27 (57.4)	75.99 ± 28.5		20.48 ± 33.11					4.79 ± 10.73		9.5 ± 18.16		11.96 ± 25.49
C-D	20 (42.6)	75.97 ± 34.7		23.51 ± 34.39					9.56 ± 23.18		15.52 ± 31.05		15.94 ± 25.12
Location			0.75				0.17			0.18		0.98		0.10
Colon	22 (46.8)	74.41 ± 26.11			17.76 ± 30.69				7.27 ± 21.22		6.81 ± 11.03		6.81 ± 9.47
Rectum	25 (53.2)	77.36 ± 34.79			25.30 ± 35.72				6.42 ± 12.90		16.69 ± 31.37		19.68 ± 32.43
Lymph node metastasis			0.57				0.10			0.10		0.93		0.65
N0	23 (48.9)	78.63 ± 30.85			15.66 ± 25.54				7.77 ± 21.27		10.72 ± 19.49		13.89 ± 27.22
N1–3	24 (51.1)	73.44 ± 31.07			27.63 ± 39.03				5.91 ± 12.27		13.35 ± 28.65		13.43 ± 23.55