XPD Lys751Gln polymorphism and esophageal cancer risk: A meta-analysis involving 2288 cases and 4096 controls

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

First author	Year	Country	Racial descent	Source of controls	Genotyping method	Histological type	Genotype distribution						P for HWE1	C
							Case			Control
							AA	AC	CC	AA	AC	CC
Xing	2002	China	Asian	Age matched	PCR-RFLP	ESCC3	367	63	3	451	70	3	0.87	0.07
Yu	2004	China	Asian	Age matched	PCR-RFLP	ESCC	108	16	11	133	17	2	0.11	0.07
Casson	2005	Canada	European	Randomly selected	PCR-RFLP	EADC4	31	21	4	34	46	15	0.93	0.40
Ye2	2006	Sweden	European	Age matched	PCR-RFLP	EADC	27	51	18	198	203	71	0.11	0.37
Ye2	2006	Sweden	European	Age matched	PCR-RFLP	ESCC	23	44	14	198	203	71	0.11	0.37
Sobti	2007	Indian	Asian	Age matched	PCR-RFLP	ESCC	52	61	7	63	77	20	0.64	0.37
Doecke	2008	Australia	Mixed	Age matched	iPLEXTM	EADC	108	124	31	575	588	174	0.22	0.35
Ferguson	2008	Ireland	European	Randomly selected	TaqMan	EADC	80	94	34	91	121	35	0.61	0.39
Tse	2008	America	Mixed	Age matched	TaqMan	EADC	104	159	49	193	208	52	0.72	0.34
Pan2	2009	America	European	Age matched	TaqMan	EADC	137	153	56	187	216	53	0.43	0.24
Pan2	2009	America	European	Age matched	TaqMan	ESCC	17	18	3	187	216	53	0.43	0.24
Zhai	2009	China	Asian	Age matched	PCR-RFLP	ESCC	167	31	2	148	51	1	0.12	0.13

¹Hardy-Weinberg equilibrium (HWE) in controls;

²The studies included esophageal adenocarcinoma (EADC), and esophageal squamous cell carcinoma (ESCC) for cases group, but controls were same;

³Esophageal squamous cell carcinoma;

⁴Esophageal adenocarcinoma. PCR: Polymerase chain reaction; RFLP: Restriction fragment length polymorphism.

Table 2 Summary odds ratios and 95% confidence interval of xeroderma pigmentosum group D Lys751Gln polymorphism and esophageal cancer risk

	CC vs AA		CA vs AA		CA/CC vs AA		CC vs CA/AA
	OR (95% CI)	P1	OR (95% CI)	P1	OR (95% CI)	P1	OR (95% CI)	P1
Total	1.19 (0.84-1.69)	0.01	1.03 (0.83-1.27)	0.01	1.05 (0.85-1.32)	0.01	1.16 (0.97-1.39)	0.062
Ethnicity
European	1.26 (0.95-1.65)	0.052	1.00 (0.64-1.54)	0.01	1.01 (0.65-1.56)	0.01	1.20 (0.94-1.55)	0.282
Asian	1.44 (0.37-5.66)	0.02	0.91 (0.71-1.15)	0.122	0.96 (0.63-1.45)	0.03	1.47 (0.38-5.71)	0.02
Histological type
EADC	1.25 (1.01-1.55)	0.052	1.13 (0.85-1.52)	0.02	0.98 (0.68-1.41)	0.01	1.18 (0.97-1.44)	0.212
ESCC	1.24 (0.56-2.70)	0.04	1.02 (0.73-1.41)	0.04	1.05 (0.74-1.50)	0.01	1.06 (0.71-1.58)	0.062

¹P value for heterogeneity;

²Estimates for fixed-effects model. OR: Odds ratio; CI: Confidence interval.