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

Study	Year	Nationality	Ethnicity	Cancer types	No. of case/control	Source of control	Genotyping method
Brockmöller [10]	1996	German	Caucasian	BLC	355/340	Hospital	PCR-RFLP
Tsuneoka [11]	1996	Japanese	Asian	HCC, LC	30/64	Population	PCR-RFLP
Wadelius [12]	1999	Swedish, Danish	Caucasian	PC	178/160	Population	PCR-RFLP
Chau [13]	2000	Japanese	Asian	HCC	29/186	Population	PCR-RFLP
Roddam [14]	2000	British	Caucasian	Leukaemia	557/952	Population	Taqman
Sachse [15]	2002	British	Caucasian	CRC	490/592	Population	PCR-RFLP
Shi [16]	2004	Chinese	Asian	EC, GC, LC BLC	607/372	Population	PCR-RFLP
Mochizuki [17]	2005	Japanese	Asian	HCC	44/843	Population	PCR-RFLP
Sugimoto [18]	2005	Japanese	Asian	GC	111/315	Hospital	PCR-RFLP
Landi [19]	2005	Spanish	Caucasian	CRC	351/321	Population	APEX
Zhou [20]	2006	Chinese	Asian	EC	127/254	Hospital	PCR-RFLP
Tamer [21]	2006	Turkish	Caucasian	CRC, GC	182/105	Hospital	RT-PCR
Xing [22]	2006	Chinese	Asian	BLC	108/112	Hospital	PCR-RFLP
Gemignani [23]	2007	European	Caucasian	LC	245/275	Hospital	Microarray
Jiang [24]	2008	Chinese	Asian	HCC	48/88	Hospital	PCR-RFLP
Yang [25]	2008	Chinese	Asian	CRC	83/112	Hospital	PCR-RFLP
Gra [26]	2008	Russian	Caucasian	Leukemia	83/177	Population	Microarray
Yadav [7]	2008	Indian	Asian	HNC	300/300	Hospital	PCR-RFLP
Khedhaier [27]	2008	Tunisian	Caucasian	BRC	304/240	Population	PCR-RFLP
Sameer [28]	2009	Palestinian	Caucasian	Leukaemia	52/200	Population	PCR-RFLP
Justenhoven [29]	2009	German	Caucasian	BC	969/991	Population	MassARRAY
Zhang [30]	2009	Chinese	Asian	EC	46/38	Hospital	PCR-RFLP
Wen [31]	2009	Chinese	Asian	BLC	87/298	Hospital	Taqman
Isomura [3]	2010	Japanese	Asian	BTC	65/566	Hospital	PCR-RFLP
Chang-Claude [4]	2010	German	Caucasian	BC	3131/5478	Population	MassARRAY
Chang [32]	2010	Chinese	Asian	HCC	68/254	Population	Allele-specific PCR
Gan [33]	2011	Chinese	Asian	BC	600/600	Population	PCR-RFLP
Sainz [34]	2011	German	Caucasian	CRC	1759/1776	Population	SNPlex
Feng [35]	2011	Chinese	Asian	HNC	300/300	Hospital	PCR-RFLP
Unpublished data	/	Chinese	Asian	HCC, CRC	245/283	Hospital	PCR-RFLP

CRC: colorectal cancer; LC: lung cancer; BC: breast cancer; BLC: bladder cancer; EC: esophagus cancer; HCC: hepatocellular carcinoma; GC: gastric cancer; PC: prostate cancer; BTC; biliary tract cancer; HNC: head neck cancer