Table 1. Information of the studies included in the meta-analysis.

						Tumor	Control
Author	Year	Country	Ethnicity	Method	Age (y)	M+/N	M+/N	Source of Controls
Sun et al. [21]	2012	China	Asian	MSP	39.3(18–65)	11/14	157/336	NT
Niyazi et al. [19]	2012	China	Asian	MSP	41.4(27–62)	19/30	1/30	BCT
Missaoui et al. [18]	2011	Tunisia	African	MSP	NA	10/14	0/8	BCT
Kim et al. [16]	2010	Korea	Asian	MSP	NA	50/69	11/41	BCT
Yang et al. [22]	2010	NE	Caucasian	QMSP	47(38–57)	18/60	5/20	BCT
Iliopoulos et al. [13]	2009	Greece	Caucasian	QMSP	41(18–62)	41/61	0/15	NT
Flatley et al. [3]	2009	UK	Caucasian	MSP	34.3(20–84)	17/42	0/40	NT
Zhao et al. [23]	2008	China	Asian	MSP	42(25–71)	34/52	0/20	BCT
Leung et al. [17]	2008	China	Asian	MSP	52.5(23–85)	60/107	0/27	AT
Feng et al. [12]	2007	USA	Caucasian	QMSP	46.8	31/63	1/16	NT
Shivapurkar et al. [20]	2007	USA	Caucasian	QMSP	NA	24/45	0/12	BCT
Jeong et al. [14]	2006	Korea	Asian	MSP	48.9(24–79)	35/78	1/24	BCT
Kang et al. [15]	2005	Korea	Asian	MSP	NA	60/82	0/17	BCT
Reesink-Peters et al. [24]	2004	NE	Caucasian	QMSP	NA	35/48	2/41	NT
Dong et al. [11]	2001	Korea	Asian	MSP	NA	27/53	0/24	BCT

Note: NE: Netherlands; UK: United Kingdom; MSP: methylation-specific polymerase chain reaction; QMSP: real-time quantitative methylation-specific polymerase chain reaction; NA: not applicable; M+: the number of methylations; N: number of total; NT: normal cervical tissues from healthy people; BCT: normal cervical tissues from patients who had benign gynecological diseases such as uterine myoma, adenomyoma, and uterine prolapse; AT: normal cervical tissues adjacent to the tumor.