Table 1. Basic characteristics of the included studies.

Study	Country	No. of EC tissue/control	Methods	Methylation site	CDKN2A expression
Zhang et al. 201128	China	35/15	MSP	Promoter, CpG islands	−
Zhou et al. 200929	China	38/20	MSP	Exon 1	−
Guida et al. 200930	Italy	40/25	MSP	Promoter, CpG islands	−
Ignatov et al. 200822	Germany	54/ND	MSP/IHC	Promoter, CpG islands	+
Suehiro et al. 200821	Japan	103/27	MSP	Promoter, CpG islands	−
Yang et al. 200626	China	134/ND	MSP	Promoter, CpG islands	−
Yun et al. 200431	China	62/10	MSP	Exon 1	+
Semczuk et al. 200323	Poland	11/ND	MSP/IHC	Promoter, CpG islands	+
Wang et al. 200224	China	36/12	MSP	Exon 1	−
Chao et al. 200027	China	48/14	MSP, RT-PCR	Exon 1	+
Zhao et al. 200032	China	38/8	MSP, RT-PCR	Exon 1	+
Wong et al. 199925	Hong Kong	49/ND	MSP	Promoter, CpG islands	−

ND: not determined.