Table 1. Characteristics of included studies in this meta-analysis.

No.	First author (Year)	Country	Ethnicity	Study design	Sample size				Methylation detection method	Materials	Source of controls	Involved clinicopathological features	Quality scores
					Control	CC	HSIL	LSIL
1	Nakashima 1999 [20]	Japan	Asian	Case-only	-	33	-	-	MSRE	Tissue	-	Tumor type	12
2	Wong 1999 [11]	China	Asian	Case-only	-	98	-	-	MSP	Tissue	-	FIGO stage, tumor grade, type	10
3	Dong 2001 [21]	Korea	Asian	Case-control	24	53	-	-	MSP and sequencing	Tissue	B	Tumor grade, type, early age	15
4	Virmani 2001 [22]	USA	Caucasian	Case-control	22	19	17	37	MSP	Tissue	H	-	13
5	Tsuda 2003 [15]	Japan	Asian	Case-only	-	53	33	9	MSP	Tissue	B	HPV infection	13
6	Gustafson 2004 [16]	USA	Caucasian	Case-control	11	-	17	11	Nested MSP	Tissue	H	-	11
7	Lea 2004 [23]	USA	Caucasian	Case-control	78	60	30	-	MSP	Tissue	H	FIGO stage, tumor grade, type, smoking, HPV infection	14
8	Yang tissue 2004 [19]	China	Asian	Case-control	100	85	-	-	MSP and sequencing	Tissue	A	FIGO stage, tumor grade, type	13
9	Yang plasma 2004 [19]	China	Asian	Case-control	30	40	-	-	MSP and sequencing	Plasma	H	-	13
10	Feng 2005 [17]	Senegal	African	Case-control	142	92	46	39	MSP	Tissue	M	-	10
11	Kim 2005 [24]	Korea	Asian	Case-control	11	41	19	11	MSP	Tissue	B	-	11
12	Lin 2005 [25]	Korea	Asian	Case-control	20	47	10	20	MSP	Tissue	B	Tumor type	11
13	Jeong 2006 [26]	Korea	Asian	Case-control	24	78	-	-	MSP	Tissue	B	FIGO stage, tumor type, early age, smoking	15
14	Kang 2006 [27]	Korea	Asian	Case-control	5	43	7	31	MSP and pyrosequencing	Tissue	B	-	13
15	Kekeeva 2006 [28]	Russia	Caucasian	Case-control	35	-	42	-	MSP	Tissue	H	-	10
16	Yang 2006 [29]	China	Asian	Case-only	-	127	-	-	MSP and sequencing	Tissue	-	FIGO stage, tumor grade, type	12
17	Ivanova 2006 [30]	Russia	Caucasian	Case-control	14	26	-	-	MSP and BSP	Tissue	A	-	11
18	Nehls 2008 [18]	Germany	Caucasian	Case-only	-	70	16	8	Nested BSM-PCR	Tissue	-	HPV infection	12
19	Attaleb 2009 [31]	Morocco	African	Case-control	20	22	-	-	MSP	Tissue	H	FIGO stage, tumor grade, HPV infection, early age	12
20	Furtado 2010 [32]	Brazil	Brazilian	Case-control	20	-	27	-	MSP	Tissue	H	HPV infection	11
21	Kim 2010 [33]	Korea	Asian	Case-control	41	69	67	32	Nested MSP	Tissue	B	-	13
22	Huang 2011 [34]	China	Asian	Case-control	15	26	49	23	MSP	Tissue	H	-	12
23	Lof-Ohlin 2011 [12]	Sweden	Caucasian	Case-only	-	109	-	-	Pyrosequencing	Tissue	-	-	11
24	Spathis 2011 [35]	Greece	Caucasian	Case-control	41	12	85	121	MSP	Tissue	H	Tumor type	12
25	Jha 2012 [36]	India	Asian	Case-control	100	125	-	-	MSP	Tissue	M	Smoking	12
26	Carestiato 2013 [13]	Brazil	Brazilian	Cross-sectional	28	29	49	35	MSP	Tissue	H	-	10
27	Banzai 2014 [37]	Japan	Asian	Case-control	24	53	22	-	MSP	Tissue	H	Tumor type	10
28	Blanco-Luquin 2015 [38]	Spain	Caucasian	Case-control	13	67	85	10	MSP	Tissue	H	Tumor type	15
29	Silveria 2015 [39]	Brazil	Brazilian	Cohort	-	40	-	-	MSP	Tissue	-	HPV infection	14

Abbreviation: CC, cervical cancer; LSIL, low-grade squamous intra-epithelial lesion; HSIL, high-grade squamous intra-epithelial lesion; MSRE, methylation-sensitive restriction endonucleases; MSP, methylation-specific PCR; BSP, bisculfite sequencing PCR; H, healthy controls; B, controls with benign gynecological diseases; A, autologous controls; M, mixed controls.