Xeroderma pigmentosum group D polymorphisms and esophageal cancer susceptibility: A meta-analysis based on case-control studies

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

Ref.	Country	Ethnicity	Control source	Cancer type	Genotype distribution (case/control)						P for HWE
					Asp312Asn			Lys751Gln
					Asp/Asp	Asp/Asn	Asn/Asn	Lys/Lys	Lys/Gln	Gln/Gln	Asp312Asn	Lys751Gln
Xing et al[21] 2002	China	Chinese	PB	ESCC	381/461	49/62	3/1	367/451	63/70	3/3	0.47	0.87
Xing et al[22] 2003	China	Chinese	PB	ESCC	286/338	38/45	1/0	278/331	44/49	3/3	0.22	0.43
Yu et al[23]2004	China	Chinese	HB	ESCC	121/136	14/16	0/0	108/133	16/17	11/2	0.49	0.11
Casson et al[24] 2005	Canada	Caucasian	HB	EADC	-	-	-	31/34	21/46	4/15	-	0.93
Ye et al[25]2006	Sweden	Swedish	PB	EADC	31/176	51/237	14/57	27/198	51/203	18/71	0.09	0.11
				ESCC	30/176	41/237	10/57	23/198	44/203	14/71	0.09	0.11
Sobti et al[26] 2007	India	Indian	HB	ESCC	-	-	-	52/63	61/77	7/20	-	0.64
Doecke et al[27] 2008	Australia	Mixed	PB	EADC	-	-	-	108/575	123/588	32/174	-	0.22
Ferguson et al[28] 2008	Ireland	Caucasian	PB	EADC	-	-	-	80/91	94/121	34/35	-	0.61
Tse et al[19] 2008	United States	Mixed	HB	EADC	117/199	150/206	43/49	104/193	159/208	49/52	0.69	0.72
Pan et al[29] 2009	United States	Caucasian	HB	ESCC	16/201	20/185	1/48	17/187	18/216	3/53	0.58	0.43
				EADC	137/201	163/185	43/48	137/187	153/216	56/53	0.58	0.43
Zhai et al[30] 2009	China	Chinese	HB	ESCC	-	-	-	167/148	31/51	2/1	-	0.12
Huang et al[29] 2012	China	Chinese	HB	ESCC	171/298	42/60	0/0	150/274	55/79	8/5	0.08	0.80
Li et al[31] 2013	China	Chinese	PB	ESCC	342/351	56/47	2/2	283/321	105/73	12/6	0.75	0.43

PB: Population-based study; HB: Hospital-based study; ESCC: Esophageal squamous cell carcinoma; EADC: Esophageal adenocarcinoma; HWE: Hardy-Weinberg equilibrium.

Table 2 Results of the meta-analysis for the xeroderma pigmentosum group D Asp312Asn polymorphism and esophageal cancer susceptibility

Study group	Co-dominant model						Dominant model			Recessive model			Additive model
	Asp/Asn vs Asp/Asp			Asn/Asn vs Asp/Asp			Asn/Asn+Asp/Asn vs Asp/Asp			Asn/Asn vs Asp/Asn+Asp/Asp			(2Asn/Asn+Asp/Asn) vs 2(Asp/Asn+Asn/Asn+Asp/Asp)
	OR (95%CI)	P	Ph	OR (95%CI)	P	Ph	OR (95%CI)	P	Ph	OR (95%CI)	P	Ph	OR (95%CI)	P	Ph
Total	1.17 (1.02, 1.33)	0.03	0.97	1.30 (1.00, 1.70)	0.05	0.75	1.18 (1.04, 1.34)	0.01	0.98	1.17 (0.91, 1.50)	0.22	0.71	1.10 (1.00, 1.21)	0.06	1.00
Cancer type
ESCC	1.09 (0.91, 1.31)	0.35	0.95	0.99 (0.54, 1.79)	0.96	0.48	1.09 (0.91, 1.30)	0.35	0.99	0.93 (0.53, 1.63)	0.79	0.40	1.06 (0.90, 1.24)	0.49	0.99
EADC	1.26 (1.03, 1.53)	0.02	0.97	1.40 (1.04, 1.89)	0.03	0.93	1.29 (1.07, 1.55)	0.01	0.99	1.24 (0.94, 1.64)	0.13	0.90	1.12 (0.99, 1.28)	0.07	0.98
Ethnicity
Chinese	1.08 (0.88, 1.33)	0.45	0.88	2.08 (0.57, 7.60)	0.27	0.66	1.10 (0.90, 1.35)	0.36	0.93	2.06 (0.57, 7.51)	0.27	0.65	1.10 (0.91, 1.33)	0.34	0.98
Non-Chinese	1.23 (1.03, 1.47)	0.02	0.95	1.27 (0.97, 1.67)	0.08	0.54	1.24 (1.05, 1.47)	0.01	0.93	1.14 (0.89, 1.47)	0.31	0.53	1.10 (0.98, 1.23)	0.11	0.92

ESCC: Esophageal squamous cell carcinoma; EADC: Esophageal adenocarcinoma; Ph: P value of the Q-test for heterogeneity.

Table 3 Results of the meta-analysis for the xeroderma pigmentosum group D Lys751Gln polymorphism and esophageal cancer susceptibility

Study group	Co-dominant model						Dominant model			Recessive model			Additive model
	Lys/Gln vs Lys/Lys			Gln/Gln vs Lys/Lys			Gln/Gln+LysGln vs Lys/Lys			Gln/Gln vs Lys/Gln+Lys/Lys			(2Gln/Gln+Lys/Gln) vs 2(Lys/Gln+Gln/Gln+Lys/Lys)
	OR (95%CI)	P	Ph	OR (95%CI)	P	Ph	OR (95%CI)	P	Ph	OR (95%CI)	P	Ph	OR (95%CI)	P	Ph
Total	1.11 (0.94, 1.31)	0.20	0.01	1.31 (0.98, 1.75)	0.07	0.03	1.14 (0.96, 1.35)	0.14	0.001	1.21 (1.02, 1.43)	0.03	0.11	1.10 (0.99, 1.22)	0.10	0.02
Cancer type
ESCC	1.13 (0.89, 1.42)	0.31	0.03	1.44 (1.01, 2.06)	0.05	0.06	1.16 (0.91, 1.49)	0.23	0.01	1.26 (0.90, 1.77)	0.17	0.08	1.13 (0.94, 1.36)	0.21	0.02
EADC	1.09 (0.85, 1.40)	0.51	0.02	1.26 (1.02, 1.56)	0.03	0.05	1.11 (0.85, 1.44)	0.45	0.01	1.19 (0.98, 1.45)	0.08	0.25	1.07 (0.98, 1.18)	0.13	0.22
Ethnicity
Chinese	1.10 (0.82, 1.47)	0.53	0.02	2.49 (1.44, 4.29)	0.001	0.64	1.18 (0.88, 1.60)	0.27	0.01	2.37 (1.38, 4.10)	0.002	0.65	1.21 (0.94, 1.56)	0.15	0.02
Non-Chinese	1.12 (0.91, 1.38)	0.30	0.03	1.13 (0.82, 1.56)	0.45	0.02	1.11 (0.89, 1.39)	0.35	0.01	1.12 (0.93, 1.34)	0.23	0.14	1.06 (0.98, 1.15)	0.16	0.27

ESCC: Esophageal squamous cell carcinoma; EADC: Esophageal adenocarcinoma; Ph: P value of the Q-test for heterogeneity.