Table 1. The main characteristics of all available studies.

First author	Year	Ethnicity	Samples	CRC		Normal
				M+	Total	M+	Total
Qi Jian	2007	Asian	Tissues	61	72	9	58
Lee BB	2009	Asian	Tissues	180	243	3	148
Gao Bo	2010	Asian	Stool	19	27	0	8
Fang Yuan	2014	Asian	Tissues	13	14	2	16
Rania AD	2014	African	Tissues	73	83	17	43
Amiot	2014	European	Stool	18	247	1	157
Amiot	2014	European	Serum	31	247	2	157
Amiot	2014	European	Urine	26	247	2	157
Samaei NM	2014	Asian	Tissues	52	125	0	125
Hu Zhang	2014	Asian	Stool	29	48	1	30
Árpád V. Patai	2015	European	Tissues	14	17	2	15
Guangyue Yin	2016	Asian	Stool	30	50	2	32

M+: the number of methylation; total: the number of case or control.