. 2016 Jul 13;11(7):e0159140. doi: 10.1371/journal.pone.0159140

Table 1. Characteristics of the 33 case-control studies included in the meta-analysis.

Literature sources	HPV(+)/	HPV(+)/	Area	Incidence	Detection Method	Control selection	HPV types
Literature sources	cases group	control group	Area	Incidence	Detection Method	Control selection	HPV types
Li Y, 1991	12/24	9/24	China	Unclear	ISH	Adjacent-normal	16
Han C, 1996	22/90	6/121	China	High	ELISA	True-normal	16
Ren ZHP, 1996	35/52	2/30	China	Lower	IHC	True-normal	16,18
Wang XJ, 1998	20/40	36/58	China	High	ISH	True-normal	16
Lu LC, 1999	15/55	43/55	China	High	ISH	Adjacent-normal	18
Cao BW 2005	207/265	203/357	China	High	PCR	True-normal	16, 18
Liu J, 2000	44/60	23/56	China	High	IHC	True-normal	16,18
Yu DH, 2000	78/112	42520	China	Lower	IHC	True-normal	16,18
Kuang ZS, 2000	23/56	4/56	China	High	PCR	Adjacent-normal	16,18
Sun LB, 2001	42542	42390	China	Lower	PCR-RT	Adjacent-normal	16
Shen ZY, 2002	115/176	105/176	China	High	PCR	Adjacent-normal	6, 11, 16, 18
Xu WG, 2003	28/40	10/50	China	Unclear	ISH	True-normal	16
Zhou XB, 2003	31/48	42605	China	High	PCR	Adjacent-normal	16
Xu CL, 2004	16/18	126/183	China	Lower	IHC	Adjacent-normal	16
Lu HS, 2004	3/40	13/39	China	Lower	IHC	Adjacent-normal	16
Lu XM, 2004	55/104	41/104	China	High	PCR	Adjacent-normal	16
Chen J, 2004	14/30	7/60	China	Lower	PCR	True-normal	16
Jiang HY, 2005	48/65	11/65	China	Lower	IHC	Adjacent-normal	16,18
Kamangar F, 2006	33/99	106/381	China	High	ELISA	True-normal	16,18,73
Zhou SM, 2009	26/82	10/80	China	High	PCR	Adjacent-normal	16
Guo F,2012	93/300	61/900	China	High	PCR	True-normal	16,18,58
Bahnassy AA, 2005	27/50	12/50	Egypt	Unclear	PCR	Adjacent-normal	16,18,11
Benamouzig R, 1992	42502	42393	France	Unclear	ISH	True-normal	6, 11, 16, 18,31, 33,
Lyronis, 2008	17/30	42548	Greece	Unclear	PCR	True-normal	16,18
Farhadi M, 2005	14/38	5/38	Iran	High	PCR	True-normal	L1,18
Far AE, 2007	33/140	12/140	Iranian	Unclear	PCR	Adjacent-normal	16.18.31.33
Astori G, 2001	42568	42476	Italy	High	PCR	Adjacent-normal	16
Tornesello ML, 2009	12/56	42609	Italy	Unclear	PCR	True-normal	6,16,8, 15, 20,25
Khurshid A, 1998	17/27	42441	Japan	Unclear	PCR	True-normal	16,18,33
Kawaguchi H, 2000	42721	25/58	Japan and China	Unclear	PCR	True-normal	16/18
Dąbrowski A, 2012	28/56	4/35	Lublin	Unclear	PCR	True-normal	16,18
Acevedo, NE, 2004	15/17	42544	México	Unclear	PCR	True-normal	16,11
Lagergren J, 1999	20/193	61/302	Sweden	Unclear	ELISA	True-normal	16,18

Lower: lower incidence of esophageal carcinoma (EC); Higher: higher incidence of EC; PCR: polymerase chain reaction; IHC: immunohistochemistry; ISH: in situ hybridization; ELISA: enzyme-linked immunosorbent assay. Adjacent-normal: the control group was obtained from the normal marginal tissue of EC during surgery. True-normal: controls were obtained from the normal esophageal epithelial tissue.