Polymorphisms of DNA repair genes XRCC1 and XRCC3, interaction with environmental exposure and risk of chronic gastritis and gastric cancer

Table 1 XRCC1 and XRCC3 allele frequencies in patients with chronic gastritis (CG) and gastric cancer (GC) and in the respective control groups C1 and C2

	Genotypes	CG (n = 202)	C1 (n = 202)	P	GC (n = 160)	C2 (n = 150)	P
		n (%)	n (%)		n (%)	n (%)
XRCC1	Arg/Arg	176 (87.1)	183 (90.6)		140 (87.5)	130 (86.7)
Codon 194	Arg/Trp	24 (11.9)	19 (9.4)		20 (12.5)	19 (12.7)
	Trp/Trp	2 (1.0)	0 (0.0)		0 (0.0)	1 (0.6)
	Arg/Trp+Trp/Trp	26 (12.9)	19 (9.4)	0.2683	20 (12.5)	20 (13.3)	0.8269
	Allele frequency	0.07	0.05		0.06	0.07
XRCC1	Arg/Arg	98 (48.5)	95 (47)		73 (45.6)	70 (46.7)
Codon 399	Arg/Gln	91 (45.0)	82 (40.6)		67 (41.9)	57 (38.0)
	Gln/Gln	13 (6.5)	25 (12.4)	0.7651	20 (12.5)	23 (15.3)	0.5035
	Arg/Gln+Gln/Gln	104 (51.5)	107 (53.0)		87 (54.4)	80 (53.3)
	Allele frequency	0.29	0.33		0.33	0.34
XRCC3	Thr/Thr	92 (45.5)	84 (41.6)		84 (52.5)	67 (44.7)
Codon 241	Thr/Met	81 (40.1)	89 (44.1)		53 (33.1)	60 (40.0)
	Met/Met	29 (14.4)	29 (14.3)	0.4221	23 (14.4)	23 (15.3)	0.1679
	Thr/Met+Met/Met	110 (54.5)	118 (58.4)		76 (47.5)	83 (55.3)
	Allele frequency	0.34	0.36		0.31	0.35

Table 2 Association between XRCC1 and XRCC3 genotype profiles and risk for chronic gastritis (CG) and gastric cancer (GC)

XRCC1		XRCC3	Groups
Codon 194	Codon 399	Codon 241	CG	GC	OR (95%CI) P	CG	C1	OR (95%CI) P	GC	C2	OR (95%CI) P
All wide-type genotypes
Arg	Arg	Thr	33	32	1.0 (reference)	33	34	1.0 (reference)	32	23	1.0 (reference)
One variant polymorphism
Trp	Arg	Thr	5	8	0.6 (0.17-2.04) 0.5469	5	6	1.2 (0.32-4.16) 1.0000	8	6	1.1 (0.32-3.44) 1.0000
Arg	Gln	Thr	51	38	1.4 (0.68-2.50) 0.5124	51	42	0.8 (0.42-1.51) 0.5234	38	34	1.2 (0.61-2.56) 0.5918
Arg	Arg	Met	50	27	2.0 (0.91-3.57) 0.1237	50	49	1.0 (0.51-1.75) 1.0000	27	34	2,0 (0.83-3.70) 0.1426
Two variant polymorphisms
Trp	Gln	Thr	3	5	0.6 (0.13-2.63) 0.7106	3	2	0.6 (0.1-4.16) 1.0000	5	4	1.1 (0.16-4.54) 1.0000
Arg	Gln	Met	43	43	1.0 (0.50-1.85) 1.0000	43	58	1.4 (0.69-2.43) 0.4309	43	39	1.2 (0.63-2.50) 0.5389
Trp	Arg	Met	10	6	1.6 (0.52-5.00) 0.5771	10	6	0.6 (0.19-1.78) 0.4106	6	7	1.6 (0.48-5.55) 0.5999
Three variant polymorphisms
Trp	Gln	Met	8	1	8.3 (0.91-100) 0.0372	8	5	0.6 (0.17-2.04) 0.5400	1	3	5.0 (0.40-50.0) 0.3113

Table 3 Association of heterozygous and mutant homozygous to the polymorphisms of codons 194 and 399 of the XRCC1 gene and to the codon 241 of the XRCC3 gene with demographic and environmental risk factors in chronic gastritis (CG) and gastric cancer (GC) patients and the respective control groups C1 and C2

	Groups	Variable
		Gender		Smoke		Drink		H pylori infection
		Male	Female	No	Yes	No	Yes	Positive	Negative
		n (%)	n (%)	n (%)	n (%)	n (%)	n (%)	n (%)	n (%)
XRCC1	CG	11 (42.3)	15 (57.7)	9 (34.6)	17 (65.4)	20 (77)	6 (23)
Arg194Trp
+	C1	10 (52.6)	9 (47.4)	13 (68.4)	6 (31.6)	17 (89.5)	2 (10.5)
Trp194Trp		P = 0.4929		P = 0.0250		P = 0.4355
XRCC1	CG	55 (53)	49 (47)	48 (46.2)	56 (53.8)	71 (68.3)	33 (31.7)	45 (53.6)	39 (46.4)
Arg399Gln	GC	67 (77)	20 (23)	24 (27.6)	63 (72.4)	35 (40.2)	52 (59.8)	9 (23.7)	29 (76.3)
+		P = 0.0005		P = 0.0084		P = 0.0001		P = 0.0021
Gln399Gln	CG	55 (52.9)	49 (47.1)	48 (46.2)	56 (53.8)	71 (68.3)	33 (31.7)
	C1	52 (48.5)	55 (51.4)	68 (63.6)	39 (36.4)	91 (85)	16 (15)
		P = 0.5335		P = 0.0111		P = 0.0039
	GC	67 (77)	20 (23)	24 (27.6)	63 (72.4)	35 (40.2)	52 (59.8)
	C2	56 (70)	24 (30)	46 (57.5)	34 (42.5)	63 (78.8)	17 (21.2)
		P = 0.3042		P = 0.0001		P = 0.0000
XRCC3	CG	57 (51.8)	53 (48.2)	46 (41.8)	64 (58.2)	77 (70)	33 (30)	44 (52.4)	40 (47.6)
Thr241Met	GC	59 (77.6)	17 (22.4)	21 (27.6)	55 (72.4)	36 (47.4)	40 (52.6)	10 (28.6)	25 (71.4)
+		P = 0.0004		P = 0.0494		P = 0.0019		P = 0.0175
Met241Met	CG	57 (51.8)	53 (48.2)	46 (41.8)	64 (58.2)	77 (47.4)	33 (52.6)
	C1	59 (50)	59 (50)	75 (63.6)	43 (36.4)	98 (79.6)	20 (20.4)
		P = 0.7838		P = 0.0010		P = 0.0110
	GC	59 (77.6)	17 (22.4)	21 (27.6)	55 (72.4)	36 (47.4)	40 (52.6)
	C2	59 (71.1)	24 (28.9)	42 (50.6)	41 (49.4)	66 (79.6)	17 (20.5)
		P = 0.3458		P = 0.0031		P = 0.0000