NAT2 polymorphism in Omani gastric cancer patients-risk predisposition and clinicopathological associations

Table 1 Distribution of seven polymorphisms in the NAT2 gene among 100 gastric cancer patients and 100 controls, and cancer risk predisposition

	G191A		C282T		T341C		C481T		G590A		A803G		G857A
	Con	C	Con	C	Con	C	Co	C	Co	C	Co	C	Co	C
Frequency	0.0	0.0	0.39	0.35	0.36	0.44	0.31	0.41	0.35	0.29	0.39	0.52	0.09	0.05
W/W	100	76	46	43	42	29	49	35	42	49	39	17	83	87
W/M	0	0	30	44	44	53	39	47	46	44	44	60	17	10
MM	0	0	24	13	14	18	12	18	12	7	17	22	0	1
P	NS		0.8		0.08		0.06		0.4		0.001		0.6
OR	-		1.1		1.3		1.8		0.7		3.1		0.7
(95% CI)			(0.6-2.1)		(0.9-1.7)		(0.9-3.3)		(0.4-1.4)		(1.5-6.3)		(0.3-1.7)
M carrier

Table 2 NAT2 genotype frequencies among 100 gastric cancer patients and 100 controls, and gastric cancer risk

Genotype	Patients	Controls	OR	95% CI
Rapid
#4#4	1	4	0.3	0.01-2.4
#12B#12B		1
#12#12		1
Intermediate
#4#5B	14	10	1.4	0.6-3.6
#4#6A	6	4	1.5	0.4-6.6
#4#6B		3
#5B#13	1	1
#6A#12C	2
#6B#13	2
#12#6B	1
#12#7B	1
#12C#6A		2
#12C#6B		1
Slow
#5A#6A	2	1
#5B#5B	18	13	1.4	0.6-3.2
#5B#5C	2	2
#5B#6A	19	13	1.5	0.6-3.3
#5B#6B	2	4	1
#5B#7A	1	1
#5B#7B	4	1	1
#5C#5A	2
#5C#5C	2	1
#5C#6A	4	4
#5C#7B	1
#6A#6A	4	11	0.4	0.1-1.3
#6A#7B	1	4
#6C#6C	5	4
#7A#7A	1	2
#7A#11A	1	2
#6A#6C	5	4
#7B#7B	1	1
#5D#5D, #5D#7A, #5D#7B, #6#7B, #7B#5A, #7B#6B, #5C#6B		71

¹Each of these genotypes had an incidence of one per genotype.

Table 3 Frequency of NAT2 phenotypes, H pylori status in gastric cancer cases and controls, and gastric cancer risk predisposition

Characteristics	Cases	Controls	Odd ratio	P
	(n = 100)	(n = 100)	(95% CI)
Nat-2 phenotype
Slow	72	73	1
Rapid + intermediate	28	27	1.1 (0.5 – 2.1)	0.90
H pylori+
Negative	28	43	1
Positive	57	41	2.1 (1.1 – 3.9)	0.02

+H pylori serology was determined in 85 patients and 84 control subjects.

Table 4 Relationship between NAT-2 and gastric cancer after adjusting the effect of H pylori

H pylori+serology	NAT-2phenotype	Cases(n = 85)	Controls(n = 84)	Total	Odd ratio(95% CI)	P
Positive	Slow	42	29	71	1
	Rapid	16	12	28	0.92 (0.35, 2.45)	0.85
Negative	Slow	17	33	50	1
	Rapid	10	10	20	1.94 (0.60, 6.35)	0.21

+H pylori serology was available for 85 patients and 84 control subjects.

Table 5 Association between NAT2 phenotype and clinicopathological characteristics in 100 gastric cancer patients

Characteristics	Slow	Intermediate and rapid	P
Age
Less than 40 yr	8	64	0.1
More than 41 yr	0	28
Sex			0.7
Male	39	17
Female	33	11
Location			0.8
Distal	41	17
Non-distal	31	11
Histologic type			0.7
Intestinal	37	16
Non-intestinal	35	12
T stage+			0.1
T1 + T2	11	7
T3 + T4	47	13
N stage+			0.7
Negative	52	7
Positive	16	3
Overall stage1			0.6
I+II	12	6
III + IV	60	22

+T and N staging was available in 78 patients were surgical resection was done.

¹Stage IV diagnosis was based on clinical staging in presence of metastatic disease.

Table 6 Independent prognostic factors for survival identified by multivariate analysis in 78 gastric cancer patients who underwent surgical resection

Characteristics	Risk Ratio	95% CI of risk ratio	P
Age			0.30
Less than 40 yr	1
More than 41 yr	2.1	0.4-9.6
Sex			0.70
Male	1
Female	0.7	0.3-1.7
Location			0.02
Distal	1
Non-distal	3.2	1.3-7.8
Histologic type			0.70
Intestinal	1
Non-intestinal	0.5	0.3-1.7
T stage			0.02
T1 + T2	1
T3 + T4	4.1	1.2-13.6
N stage			0.05
Negative	1
Positive	7.7	1-61.5
NAT2			0.18
Slow	1
Rapid	1.9	0.7-5.0
H pylori Status			0.90
Negative	1
Positive	1.1	0.4-3.0