Effect of IL-1β and IL-1RN polymorphisms in carcinogenesis of the gastric mucosa in patients infected with Helicobacter pylori in Algeria

Figures & data

Table 1 Primers and conditions for analysis of the IL-1β and IL-1RN polymorphisms

Polymorphism	Primers	Tm; PCR method (restriction enzyme); and definition of the allele
IL-1β–31	Forward: 5′-TCTTTTCCCCTTTCCTTTAACT-3′ Reverse: 5′-GAGAGACTCCCTTAGCACCTAGT-3′	52°C. PCR-RFLP (AluI); C allele: 234 bp; T allele: 150 bp and 84 bp
IL-1β–511	Forward: 5′-CTGCATACCGTATGTTCTCTGCC-3′ Reverse: 5′-GGAATCTTCCCACTTACAGATGG-3′	59°C. PCR-RFLP (DdeI); C allele: 140 bp and 49 bp; T allele: 109 bp, 49 bp and 31 bp
IL-1RN	Forward: 5′-FCTCAGCAACACTCCTAT-3′ Reverse: 5′-TCCTGGTCTGCAGGTAA-3′	60°C; PCR; 2-repeat allele: 240 bp, 3-repeat allele: 326 bp; 4-repeat allele: 412; 5-repeat allele: 498 bp

Tm: melting temperature; IL-1β-31: cluster of gene encoding interleukin-1β in the promoter region of TATA box at the −31 position; IL-1β-511: cluster of gene encoding interleukin-1β in the promoter region of TATA box at the −511 position; IL-1RN: gene encoding the anti-inflammatory antagonist (interleukin-1ra).

Table 2 Comparison between groups according to gender

	HC	AG	GC	χ ^2	p*
Female	16 (29.1%)	25 (45.5%)	14 (25.5%)
Male	16 (28.6%)	14 (25.0%)	26 (46.4%)	6.694	<0.05
Total	32 (28.8%)	39 (35.1%)	40 (36.0%)

AG: atrophic gastritis; GC: gastric carcinoma; HC: healthy controls; (*) comparison between the three groups using Chi-square test.

Table 3 Distribution of the genotypes in the study population

Genotype	HC n (%)	All n (%)	AG n (%)	GC n (%)
IL-1RN
L/L	28 (87.50)	57 (72.15)	32 (82.05)	25 (62.50)
2/L	04 (12.50)	19 (24.05)	04 (10.25)	15 (37.50)
2/2	00 (00.00)	03 (03.79)	03 (07.69)	00 (00.00)
2/L+2/2	04 (12.50)	22 (27.84)	07 (17.94)	15 (37.50)
IL-1B-511
C/C	18 (56.25)	28 (35.44)	09 (23.07)	19 (47.50)
T/C	14 (43.75)	22 (27.84)	09 (23.07)	13 (32.50)
T/T	00 (00.00)	29 (36.70)	21 (53.84)	08 (20.00)
T/C+T/T	14 (43.75)	51 (64.55)	30 (76.92)	21 (52.50)
IL-1B-31
T/T	17 (53.12)	24 (30.37)	14 (35.89)	10 (25.00)
C/T	07 (21.87)	33 (41.77)	14 (35.89)	19 (47.50)
C/C	08 (25.00)	22 (27.84)	11 (28.20)	11 (27.50)
C/T+C/C	15 (46.87)	55 (69.62)	25 (64.10)	30 (75.00)

AG: atrophic gastritis; GC: gastric carcinoma; All: atrophic gastritis and gastric carcinoma; HC: healthy controls; IL-1β-31: cluster in gene encoding interleukin-1β in the promoter region of TATA box at the -31 position; IL-1β-511: cluster in gene encoding interleukin-1β in the promoter region of TATA box at the −511 position; IL-1RN: gene encoding for the anti-inflammatory antagonist (interleukin-1ra); L: long genotype (more than three repetitions; alleles 1, 3, 4, 5); 2: short genotype (two repetitions; allele 2); C or T: single nucleotide polymorphisms.

Table 4 Regression analysis of the distribution of the genotypes in the study

Multivariate logistic regression analysis			p	OR (95% CI)
GC * HC	IL-1β (−31)	T/T	0.035	Reference
		C/C	0.010	4.614 (1.437–14.817)
		C/T	0.289	1.974 (0.562–6.939)
		C/T+C/C	0.016	3.400 (1.254–9.216)
	IL-1β (−511)	C/C	0.968	Reference
		T/T	0.800	0.880 (0.326–2.374)
		C/T	0.999	0.000 ( – )
		C/T+T/T	0.461	1.421 (0.558–3.617)
	IL-1RN	L/L	–	Reference
		L/2	0.022	4.200 (1.230–14.337)
		L/2+2/2	0.022	4.200 (1.230–14.337)
AG * HC	IL-1β (−31)	T/T	0.303	Reference
		C/C	0.131	2.429 (0.769–7.673)
		C/T	0.568	1.455 (0.402–5.260)
		C/T+C/C	0.148	0.494 (0.190–1.283)
	IL-1β (−511)	C/C	0.914	Reference
		T/T	0.671	1.286 (0.404–4.094)
		C/T	0.998	0.000 ( – )
		C/T+T/T	0.005	4.286 (1.544–11.898)
	IL-1RN	L/L	0.984	Reference
		L/2	0.999	0.000 ( – )
		2/2	0.859	0.875 (0.200–3.828)
AG * GC	IL-1β (−31)	T/T	0.497	Reference
		C/C	0.238	0.526 (0.181–1.527)
		C/T	0.581	0.737 (0.249–2.178)
		C/T+C/C	0.294	0.595 (0.226–1.570)
	IL-1β (−511)	C/C	0.009	Reference
		T/T	0.522	1.462 (0.457–4.674)
		C/T	0.026	0.264 (0.081–0.856)
		C/T+T/T	0.026	3.016 (1.144–7.952)
	IL-1RN	L/L	0.042	Reference
		L/2	0.999	0.000 ( – )
		2/2	0.012	0.208 (0.061–0.706)
		L/2+2/2	0.057	0.365 (0.129–1.030)

AG: atrophic gastritis; GC: gastric carcinoma; HC: healthy controls; OR: odds ratio. GC * HC: regression analysis of combined gastric carcinoma and healthy controls, AG * HC: regression analysis of combined atrophic gastritis and healthy controls, AG * GC: regression analysis of combined atrophic gastritis and gastric carcinoma.

IL-1β-31: cluster in gene encoding interleukin-1β in the promoter region of TATA box at the −31 position; IL-1β-511: cluster in gene encoding interleukin-1β in the promoter region of TATA box at the −511 position; IL-1RN: gene encoding the anti-inflammatory antagonist (interleukin-1ra); L: long genotype (more than three repetitions; alleles 1, 3, 4, 5); 2: short genotype (two repetitions; allele 2); C or T: single nucleotide polymorphisms.

Table 5 Distribution of genotypes among patient groups

			IL-1β-31 n (%)
Sample type			T/T	C/C	C/T	Total	Chi-square test (p)
AG	IL-1RN	L/L	14 (43.8)	08 (25.0)	10 (31.2)	32 (100.0)	0.028
		L/2	00 (00.0)	03 (75.0)	01 (25.0)	04 (100.0)
		2/2	00 (00.0)	00 (00.0)	03 (100.0)	03 (100.0)
	Total		14 (35.9)	11 (28.2)	14 (35.9)	39 (100.0)
GC	IL-1RN	L/L	07 (28.0)	09 (36.0)	09 (36.0)	25 (100.0)	0.146
		L/2	03 (20.0)	02 (13.3)	10 (66.7)	15 (100.0)
	Total		10 (25.0)	11 (27.5)	19 (47.5)	40 (100.0)
HC	IL-1RN	L/L	16 (57.1)	08 (28.6)	04 (14.3)	28 (100.0)	0.021
		L/2	01 (25.0)	00 (00.0)	03 (75.0)	04 (100.0)
	Total		17 (53.1)	08 (25.0)	07 (21.9)	32 (100.0)
Total	IL-1RN	L/L	37 (43.5)	25 (29.4)	23 (27.1)	85 (100.0)	0.005
		L/2	04 (17.4)	05 (21.7)	14 (60.9)	23 (100.0)
		2/2	00 (00.0)	00 (00.0)	03 (100.0)	03 (100.0)
	Total		41 (36.9)	30 (27.0)	40 (36.0)	111 (100.0)

Regression analysis of combined (IL-1RN vs. IL-1β-31) Chi-square test. AG: atrophic gastritis; GC: gastric carcinoma; HC: healthy controls; IL-1β-31: cluster in gene encoding interleukin-1β in the promoter region of TATA box at the −31 position; IL-1β-511: cluster in gene encoding interleukin-1β in the promoter region of TATA box at the −511 position; IL-1RN: gene encoding for the anti-inflammatory antagonist (interleukin-1ra); L: long genotype (more than three repetitions; alleles 1, 3, 4, 5); 2: short genotype (two repetitions; allele 2); C or T: single nucleotide polymorphisms.

Table 6 Distribution of genotype among patient groups

			IL-1β (−511) n (%)
Sample type			C/C	T/T	C/T	Total	Chi-square test (p)
AG	IL-1RN	L/L	09 (28.1)	18 (56.2)	05 (15.6)	32 (100.0)	0.014
		L/2	00 (00.0)	3 (75.0)	01 (25.0)	04 (100.0)
		2/2	00 (00.0)	00 (00.0)	03 (100.0)	03 (100.0)
	Total		09 (23.1)	21 (53.8)	09 (23.1)	39 (100.0)
GC	IL-1RN	L/L	15 (60.0)	05 (20.0)	05 (20.0)	25 (100.0)	0.067
		L/2	04 (26.7)	03 (20.0)	08 (53.3)	15 (100.0)
	Total		19 (47.5)	08 (20.0)	13 (32.5)	40 (100.0)
HC	IL-1RN	L/L	18 (64.3)	–	10 (35.7)	28 (100.0)	0.015
		L/2	00 (00.0)	–	04 (100.0)	04 (100.0)
	Total		18 (56.2)	–	14 (43.8)	32 (100.0)
Total	IL-1RN	L/L	42 (49.4)	23 (27.1)	20 (23.5)	85 (100.0)	0.002
		L/2	04 (17.4)	06 (26.1)	13 (56.5)	23 (100.0)
		2/2	00 (00.0)	00 (00.0)	03 (100.0)	03 (100.0)
	Total		46 (41.4)	29 (26.1)	36 (32.4)	111 (100.0)

Regression analysis of combined (IL-1RN and IL-1β-511) Chi-square test. AG: atrophic gastritis; GC: gastric carcinoma; HC: healthy controls; IL-1β-31: cluster in gene encoding interleukin-1β in the promoter region of TATA box at the −31 position; IL-1β-511: cluster in gene encoding interleukin-1β in the promoter region of TATA box at the −511 position; IL-1RN: gene encoding for the anti-inflammatory antagonist (interleukin-1ra); L: long genotype (more than three repetitions; alleles 1, 3, 4, 5); 2: short genotype (two repetitions; allele 2); C or T: single nucleotide polymorphisms.