Correlation of Helicobacter pylori and interleukin-8 mRNA expression in high risk gastric cancer population prediction

Table 1 Characteristics of gastric cancer and non-gastric cancer patients, n (%)

Characteristics	Gastric cancer n = 86	Non-gastric cancer n = 134	P value
Sex			< 0.001
Male	52 (60.47)	41 (30.60)
Female	34 (39.53)	93 (69.40)
Age			0.003
≥ 40	5 (5.81)	28 (20.90)
< 40	81 (94.19)	106 (79.10)
Mean ± SD	56 ± 11.29	48.5 ± 11.21
Alcohol drinking,	36 (41.87)	51 (38.06)	0.679
Smoking	24 (27.91)	12 (8.96)	< 0.001
Diseases
Normal	0	45 (33.83)
Benign lesion	0	46 (34.59)
Chronic active gastritis	0	42 (31.58)
Gastric cancer	86 (100)	0
Stage
Ia	-	-
Ib	-	-
IIa	1 (1.16)	-
IIb	2 (2.23)	-
IIIa	8 (9.30)	-
IIIb	41 (47.67)	-
IV	34 (39.53)	-
Histological grade
Poorly differentiated	25 (29.76)	-
Signet ring cell	36 (42.82)	-
Moderate differentiated	16 (19.05)	-
Well differentiated	7 (8.33)	-

Table 2 Serum interleukin-8 mRNA expression and Helicobacter pylori infection status detection results in gastric cancer and non-gastric cancer patients, n (%)

Variables	Gastric cancer n = 86	Non-gastric cancer n = 134	P value
H. pylori pathology			0.267
Negative	32 (37.21)	60 (44.78)
Positive	54 (62.79)	74 (55.22)
H. pylori infection status			0.121
Negative	20 (24.4)	37 (36.0)
Positive	62 (75.6)	96 (64.0)
IL-8 raw RQ			< 0.001
< 100	33 (38.37)	105 (78.36)
≥ 100	53 (61.63)	29 (21.64)
Median (IRQ)	325 (2326.37)	19.72 (105.74)
IL-8 Log 10			< 0.001
Min-0.99	5 (6.49)	36 (34.95)
1.00-1.99	16.36 (22.08)	38 (36.90)
2.00-2.99	28 (36.36)	13 (12.62)
3.00-3.99	20 (25.97)	12 (11.65)
≥ 4.00	7 (9.09)	4 (3.88)

H. pylori: Helicobacter pylori.

Table 3 Logistic models and the area of the receiver operating characteristic curves comparing Helicobacter pylori pathology results and interleukin-8 mRNA expression with/without demographic characteristics

Variable	Model 1 Crude OR (95%CI)	Model 2 Crude OR (95%CI)	Model 3 Adjusted OR (95%CI)	Model 4 Adjusted OR (95%CI)	Model 5 Adjusted OR (95%CI)
Sex	-	-	2.99 (1.72-5.20)	3.31 (1.84-5.94)	3.29 (1.83-5.93)
Age group	-	-	3.79 (1.38-10.41)	4.25 (1.47-12.34)	4.19 (1.44-12.20)
H. pylori	0.86 (0.49-1.53)	-	0.94 (0.52-1.71)	-	0.91 (0.48-1.70)
IL-8 mRNA expression ≥ 2	-	5.44 (3.08-9.62)	-	6.05 (3.32-11.02)	6.07 (3.33-11.04)
AuROC	0.48 (0.42-0.54)a	0.71 (0.64-0.77)a	0.70 (0.63-0.76)	0.80 (0.75-0.86)b	0.81 (0.75-0.86)b

^aP value difference of AuROC = 0.532;

^bP value difference of AuROC < 0.001; H. pylori: Helicobacter pylori; AuROC: Area under the receiver operating characteristic curves.

Table 4 Likelihood ratio of positive of models including interleukin-8 mRNA expression, sex, and age group

Variable	LHR+ (95%CI)	P value
Interleukin-8 mRNA expression alone	2.90 (2.02-4.16)	< 0.001
Interleukin-8 mRNA expression + age > 40 or male	3.38 (2.26-5.04)	< 0.001
Interleukin-8 mRNA expression + age > 40 + male	14.54 (4.56-46.36)	< 0.001

Table 5 Diagnostic values of each interleukin-8 mRNA expression cut-off point, 95%CI and gastric cancer diagnosis only gastric cancer cases (n = 86)

IL-8 level cut-off point	Sensitivity	Specificity	PPV	NPV	LHR+	LHR-	AuROC
1	96.8	8.7	41.7	80.0	1.06	0.37	0.53
	(92.8-100.0)	(2.4-15.0)	(30.6-52.7)	(71.1-88.9)	(0.95-1.18)	(0.04-3.16)	(0.48-0.58)
2	64.7	38.4	40.7	62.5	1.05	1.09	0.58
	(54.6-74.8)	(28.2-48.7)	(30.4-51.1)	(52.3-72.7)	(0.76-1.46)	(0.62-1.93)	(0.41-0.62)
3	41.9	69.6	48.2	64.0	1.38	1.20	0.56
	(30.9-53.0)	(59.3-79.8)	(37.0-59.3)	(53.3-74.7)	(0.75-2.52)	(0.84-1.71)	(0.45-0.67)
4	12.9	93.5	57.1	61.4	1.98	1.07	0.53
	(5.4-20.4)	(88.0-99.0)	(46.1-68.2)	(50.6-72.3)	(0.48-8.23)	(0.92-1.25)	(0.46-0.60)

P value of all AuROC = 0.832. PPV: Positive predictive value; NPV: Negative predictive value; LHR+: Positive likelihood ratio; LHR-: Negative likelihood ratio.