Predominant mucosal IL-8 mRNA expression in non-cagA Thais is risk for gastric cancer

Table 1 Characteristics of 220 Thais examined for interleukine-8 mRNA expression n (%)

Variable	Cancer (n = 86)	Benign (n =134)
Sex
Male	52 (60.5)	41 (30.6)
Female	34 (39.5)	93 (69.4)
Age (yr)
< 40	5 (5.8)	28 (20.9)
≥ 40	81 (94.2)	106 (79.1)
mean ± SD	56 ± 11.3	48.5 ± 11.2
Alcohol drinking
No	50 (58.1)	80 (59.7)
Yes	36 (41.9)	54 (40.3)
Smoking
No	62 (72.1)	122 (91.0)
Yes	24 (27.9)	12 (9.0)
Diseases
Normal	-	45 (33.8)
Benign lesion (polyps, erosion, mild superficial gastritis)	-	46 (34.6)
Chronic active gastritis	-	42 (31.6)
Cancer	86 (100.0)	-

Table 2 Serum enzyme pepsinogen I, II level and Helicobacter pylori infection detection results in Thais n (%)

Variable	Cancer (n = 86)	Benign (n = 134)	P value
PG I/II, (ng/μL), mean ± SD
I	57.39 ± 46	54.86 ± 68.5	0.780
II	19.42 ± 21	15.42 ± 11.7	0.090
PG I/II ratio
≤ 3	28 (39.4)	34 (27.9)	0.0451
> 3	43 (60.6)	88 (70.1)
H. pylori pathology
Negative	31 (36.8)	60 (44.8)	0.001
Positive	55 (63.2)	74 (55.2)
Serum IgG
Negative	31 (46.3)	57 (44.2)	0.8201
Positive	36 (53.7)	72 (55.8)
CagA genotyping in positive 23S rDNA
Negative	55 (88.7)	62 (64.6)	< 0.0011
Positive	7 (12.3)	34 (35.4)
H. pylori Infection status
True negative	20 (24.4)	37 (36.0)	0.1201
True positive	62 (75.6)	96 (64.0)

¹Some numbers are not included in the analysis due to missing laboratories entries. The statistical analysis was performed by χ² of each factor. IgG: Immunoglobulin G; CagA: Cytotoxin-associated gene A; PG: Pepsinogen; H. pylori: Helicobacter pylori.

Table 3 Molecular genetic results of cyclooxygenase-2 and interleukine-8 mRNA expression in Thais n (%)

Variable	Cancer (n = 86)	Benign (n = 134)	P value
COX2 raw RQ
No expression detection	30 (34.90)	43 (53.10)	< 0.0011
Expression detection	56 (65.10)	38 (46.90)
COX2 raw RQ
mean ± SD	41.69 ± 4.90	5.37 ± 4.20	< 0.0011
COX2 log10 (N, %)
mean ± SD	1.62 ± 0.96	0.73 ± 0.62	< 0.0011
IL-8 raw RQ
No expression detection	9 (10.47)	32 (25.37)	< 0.001
Expression detection	77 (89.53)	102 (74.63)
IL-8 raw RQ
≤ 100 or undetected	33 (38.37)	105 (78.36)	< 0.001
> 100	53 (61.63)	29 (21.64)
mean ± SD	9615.64 ± 49715.00	2262.29 ± 10454.60	< 0.010
IL-8 log10
≤ 2 or undetected	32 (37.21)	105 (78.36)	< 0.001
> 2	54 (62.79)	29 (21.64)
mean ± SD	2.62 ± 1.10	1.49 ± 1.20	< 0.010

¹Some numbers are not included in the analysis due to missing laboratory data. RQ: Relative quantity; COX2: Cyclooxygenase-2; IL-8: Interleukin-8.

Table 4 Multivariate risk analysis for Thai gastric cancer

Variable	OR	95%CI	P value
Male	4.32	2.06-9.04	< 0.001
H. pylori infection status	0.98	0.96-0.99	0.020
PG II/I ratio ≤ 3	2.06	0.94-4.47	0.060
IL-8 mRNA expression	7.97	3.75-16.97	< 0.001

OR: Odds ratio; H. pylori: Helicobacter pylori; PG: Pepsinogen; IL-8: Interleukin-8.

Table 5 Comparative means interleukine-8 mRNA expression level detection between Thai and Japanese Cancer populations divided by histopathology n (%)

Histopathology	Thai (n = 77)	Japanese (n = 17)	P value
Diffuse type	55 (71.4)	4 (23.5)	0.01
mean ± SD	2.85 ± 1.10	2.55 ± 0.52	0.95
Intestinal type	22 (28.6)	13 (76.5)
mean ± SD	2.52 ± 1.11	1.56 ± 1.06	0.01

Statistical difference between groups (P = 0.04). IL-8: Interleukin-8.