Polymorphisms of glutathione S-transferase genes and survival of resected hepatocellular carcinoma patients

Table 1 Demographic and clinical characteristics of hepatocellular carcinoma patients

Variable	Our cohort		Hong Kong cohort
	n	%	n	%
Total	214	100	401	100
Age (yr)
≤ 55	108	50.5	NA	NA
> 55	106	49.5	NA	NA
Gender
Male	176	82.2	322	80.3
Female	38	17.8	79	19.7
Smoking behavior
Yes	70	32.7	223	55.6
No	144	67.3	178	44.4
Cirrhosis
Present	126	58.9	229	57.1
Absent	88	41.1	172	42.9
Child-Pugh score
A	172	80.4	390	97.3
B	42	19.6	11	2.7
AFP level (ng/mL)
< 200	100	46.7	NA	NA
≥ 200	114	53.3	NA	NA
Tumor size
< 5 cm	102	47.7	NA	NA
≥ 5 cm	112	52.3	NA	NA
TNM stage
I + II	119	55.6	177	44.1
III	95	44.4	224	55.9
Outcome
Dead	111	51.9	272	67.8
Alive	103	48.1	129	32.2

Table 2 Summarized information of selected tagging SNPs in GST genes

Gene	Tagging SNPs	bp position	Ref SNP alleles	MAF_CHB
GSTA1	rs6917150	Chr 6: 52760414	T/C	0.338
GSTA4	rs385636	Chr 6: 52948896	A/G	0.174
GSTM2	rs638820	Chr 1: 110011429	T/C	0.344
GSTM3	rs1109138	Chr 1: 110079472	G/A	0.167
	rs7483	Chr 1: 110081224	A/G	0.244
GSTO1	rs2282326	Chr 10: 106010388	A/C	0.244
	rs17116779	Chr 10: 106021185	G/A	0.078
GSTO2	rs156699	Chr 10: 106043631	T/C	0.222
	rs7085725	Chr 10: 106050199	T/C	0.122
	rs157077	Chr 10: 106027884	A/G	0.378
GSTP1	rs4147581	Chr 11: 67108161	G/C	0.273
	rs2370141	Chr 11: 67105105	A/G	0.181

MAF (minor allele frequency) was derived from CHB (Chinese Han people in Beijing) population in HapMap website (http://hapmap.ncbi.nlm.nih.gov/).

Table 3 Associations between polymorphisms of tagging SNPs in GST genes and overall survival in hepatocellular carcinoma patients

Gene	Tagging SNP	Genotype	Outcome, n (%)		HR (95%CI)	P value
			Dead	Alive
GSTA1	rs6917150	WW	48 (51.6)	45 (48.4)	1 (ref)
		WV + VV	63 (52.1)	58 (47.9)	1.01 (0.69-1.48)	0.961
GSTA4	rs385636	WW	82 (55.4)	66 (44.6)	1 (ref)
		WV + VV	29 (43.9)	37 (56.1)	0.71 (0.46-1.09)	0.117
GSTM2	rs638820	WW	42 (51.9)	39 (48.1)	1 (ref)
		WV + VV	69 (51.9)	64 (48.1)	1.13 (0.77-1.67)	0.526
GSTM3	rs1109138	WW	85 (54.1)	72 (45.9)	1 (ref)
		WV + VV	26 (45.6)	31 (54.4)	0.81 (0.52-1.26)	0.353
	rs7483	WW	63 (56.2)	49 (43.8)	1 (ref)
		WV + VV	48 (47.1)	54 (52.9)	0.94 (0.64-1.38)	0.760
GSTO1	rs2282326	WW	60 (56.1)	47 (43.9)	1 (ref)
		WV + VV	51 (47.7)	56 (52.3)	0.92 (0.63-1.35)	0.675
	rs17116779	WW	99 (51.0)	95 (49.0)	1 (ref)
		WV + VV	12 (60.0)	8 (40.0)	0.95 (0.52-1.75)	0.869
GSTO2	rs156699	WW	64 (50.0)	64 (50.0)	1 (ref)
		WV + VV	47 (54.7)	39 (45.3)	1.10 (0.75-1.62)	0.612
	rs7085725	WW	81 (46.0)	95 (54.0)	1 (ref)
		WV + VV	30 (78.9)	8 (21.1)	1.60 (1.03-2.47)a	0.035a
	rs157077	WW	50 (58.1)	36 (41.9)	1 (ref)
		WV + VV	61 (47.7)	67 (52.3)	0.78 (0.54-1.14)	0.198
GSTP1	rs4147581	WW	57 (55.3)	46 (44.7)	1 (ref)
		WV + VV	54 (48.6)	57 (51.4)	0.68 (0.46-0.99)a	0.042a
	rs2370141	WW	74 (52.1)	68 (47.9)	1 (ref)
		WV + VV	37 (51.4)	35 (48.6)	0.90 (0.61-1.34)	0.597

^aP < 0.05 was considered statistically significant. WW: Homozygous wild-type genotype; WV: Heterozygous genotype; VV: Homozygous variant genotype; SNP: Single nucleotide polymorphisms.

Table 4 Stratified analysis on the association between GSTO2: rs7085725 and GSTP1: rs4147581 genotype and overall survival of hepatocellular carcinoma patients

Variable	GSTO2: rs7085725				GSTP1: rs4147581
	Dead/Alive		HR (95%CI)	P value	Dead/Alive		HR (95%CI)	P value
	WW	WV + VV			WW	WV + VV
Age (yr)
≤ 55	32/52	19/5	1.86a (1.02-3.38)	0.044a	28/25	23/32	0.52a (0.30-0.92)	0.024a
> 55	49/43	11/3	1.71 (0.89-3.31)	0.110	29/21	31/25	0.92 (0.55-1.54)	0.755
Gender
Male	62/83	26/5	1.83a (1.14-2.94)	0.013a	44/38	44/50	0.64a (0.42-0.99)	0.042a
Female	19/12	4/3	0.76 (0.22-2.64)	0.663	13/8	10/7	1.06 (0.45-2.50)	0.902
Smoking behavior
No	52/67	19/6	1.35 (0.78-2.37)	0.287	35/26	36/47	0.58a (0.36-0.93)	0.024a
Yes	29/28	11/2	2.59a (1.27-5.27)	0.009a	22/20	18/10	1.06 (0.56-1.99)	0.870
Cirrhosis
Absent	41/30	12/5	1.21 (0.62-2.35)	0.579	23/17	30/18	0.91 (0.52-1.59)	0.746
Present	40/65	18/3	2.00a (1.11-3.59)	0.020a	34/29	24/39	0.50a (0.29-0.85)	0.011a
Child-Pugh score
A	61/87	17/7	2.28a (1.32-3.93)	0.003a	39/44	39/50	0.83 (0.53-1.30)	0.422
B	20/8	13/1	0.97 (0.47-2.03)	0.940	18/2	15/7	0.45a (0.22-0.90)	0.024a
AFP level (ng/mL)
< 200	39/40	14/7	1.09 (0.57-2.11)	0.793	26/17	27/30	0.51a (0.29-0.89)	0.018a
≥ 200	42/55	16/1	2.40a (1.34-4.29)	0.003a	31/29	27/27	0.85 (0.51-1.44)	0.552
Tumor size
< 5 cm	37/50	10/5	1.51 (0.74-3.06)	0.254	23/26	24/29	0.77 (0.43-1.38)	0.379
≥ 5 cm	44/45	20/3	1.59 (0.90-2.80)	0.109	34/20	30/28	0.60a (0.37-1.00)	0.048
TNM stage
I + II	44/60	11/4	1.24 (0.61-2.53)	0.555	27/26	28/38	0.64 (0.37-1.10)	0.104
III	37/35	19/4	1.66 (0.94-2.93)	0.081	30/20	26/19	0.75 (0.43-1.30)	0.311

^aP < 0.05 was considered statistically significant. WW: Homozygous wild-type genotype; WV: Heterozygous genotype; VV: Homozygous variant genotype.

Table 5 Cumulative effects of unfavorable genotypes on overall survival of hepatocellular carcinoma patients

Group (number of unfavorable genotypes1)	Death/Total	HR (95%CI)	P value
In all patients
Group 1 (0)	44/95	1 (ref)
Group 2 (1)	47/97	1.08 (0.71-1.63)	0.730
Group 3 (2)	20/22	1.70a (1.30-2.22)	< 0.001a
P for trend			0.004a
In patients with age ≤ 55
Group 1 (0)	18/47	1 (ref)
Group 2 (1)	26/45	1.01 (0.52-1.95)	0.975
Group 3 (2)	14/16	2.00a (1.40-3.86)	< 0.001a
P for trend			0.003a
In patients with male gender
Group 1 (0)	36/82	1 (ref)
Group 2 (1)	34/75	0.97 (0.60-1.56)	0.898
Group 3 (2)	18/19	1.94a (1.45-2.59)	< 0.001a
P for trend			0.002a
In patients with cirrhosis
Group 1 (0)	20/56	1 (ref)
Group 2 (1)	24/56	1.29 (0.71-2.35)	0.410
Group 3 (2)	14/14	1.97a (1.39-2.79)	< 0.001a
P for trend			0.001a

¹Unfavorable genotypes: GSTO2: rs7085725 (WV or VV) and GSTP1: rs4147581 (WW).

^aP < 0.05 was considered statistically significant. WW: Homozygous wild-type genotype; WV: heterozygous genotype; VV: Homozygous variant genotype.

Table 6 Modulating effects of smoking on hepatocellular carcinoma overall survival by GSTO2: rs7085725 or GSTP1: rs4147581 genotypes

SNP and variables	Death/total	HR (95%CI)	P value
In patients with WW genotype of GSTO2: rs7085725
Smoking behavior
No smoking	52/119	1 (ref)
Smoking	29/57	1.04 (0.82-1.31)	0.757
Smoking quantity (packs-year)1
0	52/119	1 (ref)
> 0 and < 20	20/45	1.06 (0.82-1.37)	0.667
≥ 20	9/12	0.99 (0.76-1.30)	0.956
In patients with WV + VV genotypes of GSTO2: rs7085725
Smoking behavior
No smoking	19/25	1 (ref)
Smoking	11/33	1.52 (1.02-2.26)a	0.042a
Smoking quantity (packs-year)1
0	19/25	1 (ref)
> 0 and < 20	9/11	1.42 (0.93-2.16)	0.106
≥ 20	2/2	2.07 (1.13-3.76)	0.018a
In patients with WW genotype of GSTP1: rs4147581
Smoking behavior
No smoking	35/61	1 (ref)
Smoking	22/42	0.95 (0.72-1.24)	0.697
Smoking quantity (packs-year)1
0	35/61	1 (ref)
> 0 and < 20	15/33	0.97 (0.71-1.31)	0.824
≥ 20	7/9	0.95 (0.71-1.28)	0.754
In patients with WV + VV genotypes of GSTP1: rs4147581
Smoking behavior
No smoking	36/83	1 (ref)
Smoking	18/28	1.27 (0.95-1.69)	0.101
Smoking quantity (packs-year)1
0	36/83	1 (ref)
> 0 and < 20	14/23	1.27 (0.93-1.74)	0.128
≥ 20	4/5	1.16 (0.81-1.66)	0.426

¹To calculate pack-years of smoking, the average of number of cigarettes smoked per day was divided by 20 to give packs per day and multiplied by the total number of years of smoking.

^aP < 0.05 was considered statistically significant. WW: Homozygous wild-type genotype; WV: Heterozygous genotype; VV: Homozygous variant genotype; SNP: Single nucleotide polymorphisms.