Is Parkinson disease associated with lysosomal integral membrane protein type-2?: Challenges in interpreting association data

Several genetic risk factors have been identified for Parkinson disease (PD), including mutations in glucocerebrosidase (GBA1). Recently, two single nucleotide polymorphisms (SNPs) described as SCARB2 SNPs were reported to be associated with PD. SCARB2 is an attractive candidate gene for PD as it encodes for lysosomal integral membrane protein type 2 (LIMP-2), a protein involved in transporting glucocerebrosidase from the ER to the lysosome. The first SNP, rs6812193, located 64 kb upstream of SCARB2, was identified in a Parkinson disease Genome Wide Association study of Americans with European ancestry (p = 7.6 × 10^? 10, OR = 0.84), but was not replicated in a study in the Han Chinese. The second SNP, rs6825004, located within intron 2 of SCARB2 was reported in an association study of Parkinson disease in Greece (p = 0.02, OR = 0.68). We explored whether the two SNPs impact SCARB2 expression or LIMP-2 protein levels, testing fifteen control samples. First, the genotypes for each subject were determined for both SNPs using a Taqman assay. Then, RNA and protein were extracted from the corresponding cell pellets. Neither the relative RNA expression by real-time PCR, nor LIMP-2 levels on Western blots correlated with SNP genotype. Thus, these two reported SNPs may not be related to SCARB2 and demonstrate the challenges in interpreting some association studies. While LIMP-2 could still play a role in PD pathogenesis, this study does not provide evidence that the SNPs identified are in fact related to LIMP-2.     

Involvement of genes encoding apoptosis regulatory factors (FAS,FASL, TRAIL,BCL2, TNFR1 and TNFR2) in the pathogenesis of autoimmune thyroid diseases

Apoptosis is necessary for the maintenance of self-tolerance by eliminating autoreactive immune cells in the periphery. To clarify the association between the pathogenesis of autoimmune thyroid disease (AITD) and genes encoding apoptosis regulatory factors, we genotyped the FAS −1377G/A, −670A/G, FASL −844C/T, TRAIL −716C/T, BCL2 −938C/A, +127G/A, TNFR1 −383A/C and TNFR2 +676T/G polymorphisms. The frequencies of the FASL −844CC and BCL2 −938AA genotypes were significantly lower in AITD patients than in control subjects (P = 0.0101 and 0.0307, respectively). The frequency of the TNFR2 +676TT genotype was significantly lower in Graves’ disease (GD) patients than in controls (P = 0.0284). The serum sFasL level was significantly higher in GD and Hashimoto’s disease (HD) patients than in control subjects (P = 0.0003 and 0.0017, respectively). The serum sFasL levels in control subjects were significantly lower than those in intractable GD, GD in remission, and HD without treatment (P = 0.0310, 0.0007 and 0.0002, respectively). The serum sFasL levels in HD with treatment were significantly lower than those in HD without treatment (P = 0.0490). The polymorphisms in genes encoding apoptosis regulatory factors (FASL, BCL2) and serum levels of sFasL may be associated with immune dysregulation.     

A tug-of-war between tolerance and rejection – New evidence for 3′UTR HLA-G haplotypes influence in recurrent pregnancy loss

HLA-G is a molecule essential to the maintenance of the maternal-fetal interface tolerance, thus contributing to a healthy pregnancy. Here we investigate the role of HLA-G single nucleotide polymorphisms (SNPs) and whether a specific HLA-G haplotype influence or not recurrent pregnancy loss (RPL) risk. A total of 296 DNA samples from RPL (N = 140) and controls (N = 156) were evaluated. The HLA-G 3′UTR region was sequenced and eight major SNPs were evaluated (14pb insertion/deletion, +3003T/C, +3010C/G, +3027C/A, +3035C/T, +3142G/C, +3187A/G, +3196C/G). A high linkage disequilibrium (LD) among all pairs and a perfect LD between +3010C/G and +3142G/A (D′ = 1.0, r² = 1.0) were observed. Our data showed an increased risk to +3010CC genotype carriers in comparison with control [odds ratio (OR) 2.05 95% confidence interval (CI) 1.05–4.00, p = 0.035] and to a decreased risk of RPL in +3142CC genotype carriers (OR = 0.49 95%CI 0.25–0.95, p = 0.035) and +3187AG genotype carriers (OR = 0.58 95%CI 0.35–0.94, p = 0.029). A total of eight haplotypes were observed in the sample, being UTR-1 and UTR-2 the most represented. An association between UTR-1 haplotype carriers with a reduced risk of both RPL and secondary RPL was observed. Our results indicate that the HLA-G 3′UTR plays important roles in RPL and might be an important marker of susceptibility to this, and possible to other, pregnancy disorders.     

PTPN22 polymorphisms,but not R620W,were associated with the genetic susceptibility of systemic lupus erythematosus and rheumatoid arthritis in a Chinese Han population

ObjectivesThe present study aimed to detect a possible association between PTPN22 gene polymorphisms and rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) in a Chinese Han population.Methods7 PTPN22 SNPs were genotyped in 358 patients with RA and 713 patients with SLE, as well as 564 RA controls and 672 SLE controls by Restriction Fragment Length Polymorphism (RFLP). Association analyses were conducted on the whole data set. Significant relationships were also examined between clinical features and SNPs for both RA and SLE.ResultsRs2476601 was lack of polymorphism with a ⩽0.1% frequency in both SLE and RA patients and healthy controls in our study. The two SNPs rs1217414 and rs3811021 of PTPN22 shown strong association with both SLE (rs1217414T: p_adj = 6.07e−004, OR = 0.57; rs3811021C: p_adj = 4.68e−005, OR = 0.65) and RA (rs1217414T: p_adj = 2.01e−008, OR = 0.26; rs3811021C: p_adj = 0.028, OR = 0.70). And the rs3765598 revealed a strong risk factor for SLE (p = 9.38e−009, p_adj = 6.57e−008, OR = 1.93), but not for RA (p = 0.48, OR = 1.12). Moreover, protective haplotype ACTTC in RA (p = 7.73e−016, p_adj = 5.51−015, OR[95%CI] = 0.02[0.002–0.10]) and SLE (p = 8.29e−018, p_adj = 5.80e−017, OR[95%CI] = 0.11[0.06–0.21]) were observed. In addition, the distribution of risk haplotypes ACGTC and GCTTT in RA (ACGTC: p = 0.0006, p_adj = 0.004, OR[95%CI] = 1.85[1.29–2.63]; GCTTT: p = 2.62e−005, p_adj = 1.85e−004, OR[95%CI] = 2.40[1.57–3.65]) and SLE (ACGTC: p = 0.0006, p_adj = 0.004, OR[95%CI] = 1.85[1.29–2.63]; ACGTC: p = 7.74e−011, p_adj = 6.81e−010, OR[95%CI] = 2.21[1.12–3.34]; GCTTT: p = 2.40[1.57–3.65], p_adj = 2.26e−006, OR[95%CI] = 2.64[1.79–3.87]) were significant different from that in controls. Furthermore, significant association was observed between the PTPN22 rs3765598 and antinuclear antibodies 1 (ANA1) in SLE.ConclusionsOur data provide strong evidence that the rs1217414 and rs3811021 in PTPN22 gene might be common protective factors contributed to SLE and RA susceptibility in the Chinese Han population. While, the rs3765598 might increase the genetic susceptibility of SLE, but not RA.     

FCRL3 gene polymorphisms as risk factors for rheumatoid arthritis

BackgroundRheumatoid arthritis (RA) is a common chronic systemic autoimmune disease. As a member of FCRLs clusters, Fc receptor-like 3 (FCRL3) has been recognized as a neoteric autoimmune activation factor for RA. The aim of our study is to evaluate the correlation between four single-nucleotide polymorphisms (SNPs) on FCRL3 and RA risk in a Chinese Han population.Material and methodsThe hospital-based case-control study included 630 RA patients together with 696 healthy individuals as the control group and all subjects are Chinese ancestry. Four tagging single-nucleotide polymorphisms (tag-SNPs) on FCRL3 were selected and genotyped by TaqMan assay. Odds ratios (ORs) and 95% confidence intervals (CIs) were employed to evaluate the correlations between FCRL3 polymorphisms and RA. A systematic meta-analysis was also carried out based on the present study and previously published studies to further examine the association between FCRL3 variations and RA risk.ResultsSignificant association was found between −169T/C SNP and RA risk (CC vs. TT, OR = 1.62, 95% CI = 1.18–2.22; TC/CC vs. TT, OR = 1.47, 95% CI = 1.18–1.84; C vs. T, OR = 1.32, 95% CI = 1.12–1.54). Apart from that, mutations of −169T/C was significantly correlated with rheumatoid factor (RF) and anti-cyclic citrullinated peptide antibody (ACPA) positive status. The meta-analysis also suggested that −169T/C mutation might have positive correlation with risk of RA in the overall population, particularly for Asian. Stratified analysis based on clinical characteristics of RF and ACPA also provided evidence that −169T/C polymorphisms could alter phenotypes of RA.ConclusionThe FCRL3 −169T/C variant was significantly linked with an increased RA risk in the Chinese Han population. Moreover, this meta-analysis also provides notion that −169T/C variant could act as a susceptible factor for RA. However, further investigations about the functional impacts of this polymorphism are essential to confirm the above conclusions.     

Role of the Fyn −93A>G polymorphism (rs706895) in acute rejection after liver transplantation

The tyrosine kinase Fyn phosphorylates tyrosine residues on key targets involved in early T-cell signal transduction. T-cell signal transduction is one essential step for acute transplant rejection. The aim of this study was to evaluate the association of Fyn −93A>G single nucleotide polymorphism (SNP) (rs706895) with the susceptibility to acute rejection episodes in liver transplantation. In total, 72 liver transplant recipients with one biopsy proven acute rejection (S-BPAR), 56 with multiple BPAR (M-BPAR), 105 without BPAR (No-BPAR), and 145 healthy controls were enrolled in this case-control study. The SNP was genotyped by polymerase chain reaction–allele specific restriction enzyme analysis (PCR–ASRA) and was analyzed for a recessive and a dominant model. The Fyn −93G allele exhibits in healthy controls a statistically significant lower frequency than in liver recipients (18% vs. 24%; p = 0.046) or in liver recipients with BPAR (18% vs. 27%; p = 0.017). However, the genotype and allele frequencies of the Fyn −93A>G SNP demonstrate no significant differences between recipients with acute rejection episodes (S-BPAR and M-BPAR) and No-BPAR recipients. Thus our results provide no evidence that the Fyn −93A>G SNP contributes to the susceptibility to acute liver transplant rejection in a Caucasian population.     

Tumor necrosis factor-alpha single nucleotide polymorphisms in juvenile systemic lupus erythematosus

BackgroundJuvenile systemic lupus erythematosus (JSLE) is a multi-system autoimmune disorder of unknown origin. Given the importance of the contribution of pro-inflammatory cytokines, including tumor necrosis factor-alpha (TNF-α), towards the pathogenesis of JSLE, this study was performed to assess TNFA gene polymorphisms in a case-control study.MethodsFifty nine patients with JSLE were enrolled in this study as case group and compared with healthy control subjects. The frequency of alleles, genotypes, and haplotypes of TNFA single-nucleotide polymorphisms (SNPs) at positions −308 and −238 were evaluated, using polymerase chain reaction with sequence-specific primers method.ResultsThe G allele at position −238 in TNFA promoter region was significantly more frequent in patients with JSLE than in the healthy controls (P value < 0.001), while the frequency of A allele at the same position was significantly lower than controls. Furthermore, a significant positive association for G/G genotype at the same position was detected in patients’ group compared with control subjects (P value < 0.001). The GA haplotype of TNFA (positions −308, −238) was significantly less frequent in case group than in controls (P value < 0.001), while GG was the most frequent haplotype for TNFA in the patient group, compared to controls (P value < 0.01).ConclusionsPro-inflammatory cytokine gene polymorphisms may influence susceptibility to JSLE. Particular TNFA gene variants are associated with JSLE and could be used as a genetic marker for susceptibility to JSLE.     

Association of PTPN22 gene polymorphisms with chronic hepatitis B virus infection in Chinese Han population

Lymphoid protein tyrosine phosphatase encoded by protein tyrosine phosphatase non-receptor 22 (PTPN22) gene plays an important regulatory role in T- and B-cell activation. This study investigated PTPN22 −1123G/C and intron 16 T/C polymorphisms in 372 patients with chronic hepatitis B virus (HBV) infection, 72 HBV infection resolvers and 273 healthy controls. Genotypic association tests between groups assuming codominant, dominant or log-additive genetic models were performed. In recessive model, PTPN22 −1123G/C genotype GG in healthy controls was more frequent than infection resolvers (P = 0.037, OR = 3.606, 95%CI = 1.079–12.053) and this genotype in HBV patients was more frequent than resolvers although the difference was not significant (P = 0.059). The PTPN22 intron 16 T/C genotype TC in cirrhosis patients was significantly higher than asymptomatic carriers (ASC) in codominant (P = 0.028, OR = 9.792, 95%CI = 1.281–74.832) and overdominant (P = 0.025, OR = 10.142, 95%CI = 1.332–77.214) models. This genotype in hepatocellular carcinoma (HCC) patients was significantly higher than ASC in codominant (P = 0.034, OR = 9.200, 95%CI = 1.176–71.990) and overdominant (P = 0.030, OR = 9.677, 95%CI = 1.241–75.442) models. These findings suggest that PTPN22 polymorphisms may predispose the chronicity or the development of cirrhosis and HCC in HBV infection.     

Contribution of dendritic cell immunoreceptor (DCIR) polymorphisms in susceptibility of systemic lupus erythematosus and primary Sjogren’s syndrome

Dendritic cell immunoreceptor (DCIR) has previously shown an association with rheumatoid arthritis (RA) in Caucasians and Han Chinese. This study was aimed to further investigate whether DCIR polymorphisms are novel susceptibility factors for other autoimmune diseases, i.e. systemic lupus erythematosus (SLE) and primary Sjogren’s syndrome (SS). A total of 1502 patients with SLE, 476 patients with primary SS, and 1278 non-related healthy controls were enrolled in the study. The single-nucleotide polymorphisms (SNPs) rs2377422 and rs10840759 were genotyped using TaqMan assay. The differences in allelic and genotypic distribution between two groups were assessed using Pearson chi-square test, and logistic regression adjusting for age and sex, respectively. P-value <0.025 was considered statistically significant by Bonferroni correction. The SNP rs2377422 confers an increased susceptibility risk to both SLE (allele model: P = 7.65 × 10⁻⁴, OR 1.20; genotype recessive model: P = 0.012, OR 1.29), and primary SS (allele model: P = 3.74 × 10⁻⁴, OR 1.31; genotype dominant model: P = 1.62 × 10⁻⁴, OR 2.02). There is no association between rs10840759 and SLE or primary SS. In conclusion, DCIR SNP rs2377422 is a novel genetic susceptibility factor for both SLE and primary SS.     

Genomic structure of grass carp Mx2 and the association of its polymorphisms with susceptibility/resistance to grass carp reovirus

Mx (myxovirus-resistant) proteins are induced by interferon and inhibit viral replication in many vertebrates. In the present study, the organization of grass carp (Ctenopharyngodon idella) Mx2 (CiMx2) gene sequence was elucidated and its single nucleotide polymorphisms (SNPs) were investigated to explore their association with susceptibility/resistance to grass carp reovirus (GCRV). The CiMx2 genomic sequence is composed of 8108 bp, containing 12 exons and 11 introns. Exon size ranges from 29 to 648 bp, and intron size varies from 89 to 1925 bp. Five SNPs were discovered in the complete sequence of CiMx2 genomic sequence and four of them were found to be located in introns. The 7 C/T locus is a non-synonymous mutation. The genotype and allele distribution were examined by PCR-RFLP in susceptible and resistant fish. The results indicate that genotypes at the 1191 C/A and 1205 G/A loci are significantly associated with the resistance of grass carp to GCRV (P<0.05). To further verify the correlation, an additional infection experiment was carried out. The mortality in CC genotype individuals (0%) at 1191 C/A locus was significantly lower than that in AA (61.11%) and AC (71.17%) genotypes (P<0.05). At 1205 G/A site, no AA genotype individual was found; the mortality in AG genotype group was 53.06%, which was significantly lower than that in GG genotype group (90.48%) (P<0.05). The results demonstrate that genotype 1191 AC, 1191 AA and 1205 GG individuals are susceptible to GCRV, while 1191 CC and 1205 AG are resistant. The 7 C/T and 528 C/T loci are in high linkage disequilibrium, however, no significant association was found between the haplotype and resistance to GCRV (P>0.05). These results provide potential markers for further investigation of selective breeding of resistant grass carp to GCRV.     

CCR2-64I polymorphism is associated with Non-Small Cell Lung Cancer in Tunisian patients

Single nucleotide polymorphism (SNPs) in genes coding for chemokines may be associated with some cancer. The purpose of this study was to investigate the impact of CCR2-64I and CXCL12-3′A SNPs on the susceptibility and the clinicopathological characteristics of NSCLC (Non-Small Cell Lung Cancer) in the Tunisian population. 170 NSCLC patients and 225 healthy controls screened by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis were enrolled. A significant association for the homozygous genotype CCR2 64I/64I with lung cancer risk was observed (P = 0.004). An increased significant frequency of the -64I allele (P = 0.0006) was noted in the patient’s group. Clinical analysis indicated a positive association of the -64I allele among squamous cell lung carcinoma patients (P = 0.003). The CCR2 mRNA extracted from peripheral blood mononuclear cells (PBMC) was found highly expressed in NSCLC patients compared to controls. The same higher levels were found in patients carrying the CCR2 64I/64I genotype. No significant association was retrieved with CXCL12-3′A polymorphism. In conclusion, our results revealed that the subjects with -64I allele of CCR2-64I gene polymorphism, expressed a significantly higher risk for NSCLC risk without influence on its pathological progression.     

Evidence of association of interleukin-23 receptor gene polymorphisms with Egyptian rheumatoid arthritis patients

BackgroundThe identification of additional genetic risk factor is an on-going process that will aid in the understanding of rheumatoid arthritis (RA) aetiology. A genome-wide association scan in Crohn’s (CD) disease highlighted the interleukin-23 receptor (IL23R) gene as a susceptibility factor. Since the IL-23/IL-17 pathway is known to associate with other autoimmune disease, including rheumatoid arthritis and systemic sclerosis, we hypothesised that IL23R could be a shared susceptibility gene. The rare allele of IL23R single nucleotide polymorphism (SNP) rs11209026 (Arg381Gln) confers strong protection against CD. Our aim was to analyse IL23R SNP (rs11209026, rs2201841, and rs10889677) and to detect its association with RA in Egyptian patients.MethodsA group of Egyptian patients with RA (n = 120) and apparently healthy persons as controls (n = 120) was genotyped for rs11209026, rs2201841 and rs10889677 by real time/polymerase chain reaction (real-time/PCR) for the first SNP and restriction fragment length polymorphism/PCR (RFLP/PCR) in the last two SNPs.ResultsOur data emphasise that the AA genotype of rs11209026 (Arg381Gln) was significantly associated with RA patients compared to the controls (P value = 0.001).We did not find any significant association between either rs2201841 or rs10889677 and the development of rheumatoid arthritis (P value = 1.000 & 0.562 respectively).ConclusionOur results suggest that IL23 receptor AA genotype variant of rs11209026 would contribute to RA aetiology; consequently, it might be a genetic marker for RA. We need to address the subgroup of patients who will benefit from the selective suppression of the IL23 signalling which would represent new perspectives toward a personalized therapy of RA patients by further studies.     

Association study of rs924080 and rs11209032 polymorphisms of IL23R-IL12RB2 in a Northern Chinese Han population with Behcet’s disease

ObjectivesTwo genome-wide association studies (GWAS) have identified the IL-23 receptor- IL-12 receptor β2 (IL23R-IL12RB2) as the susceptibility genetic region in Turkish and Japanese population with Behçet’s disease (BD). We investigated the association of this region with BD in a Northern Chinese Han population.MethodsA total of 407 patients with BD and 421 healthy controls were genotyped for single nucleotide polymorphisms (SNPs) rs924080 and rs11209032 using the Sequenom MassArray system.ResultsStatistically significant associations with BD were detected at two SNPs namely, rs924080 and rs11209032, both, by allele analysis (OR = 1.58, 95% CI = 1.25–2.00, P_c = 2.52 × 10⁻⁴, and OR = 1.45, 95% CI = 1.19–1.76, P_c = 3.46 × 10⁻⁴, respectively), and genotype analysis (P_c = 1.22 × 10⁻³ and P_c = 1.77 × 10⁻³, respectively). Significant differences were observed in the genotype frequency distribution for these SNPs under the additive, dominant and recessive models (all P_c < 0.05). The haplotypes (AT and GC) formed by the two SNPs were associated with BD (all permutation P < 0.05). A meta-analysis also appeared to support the association of the two SNPs with BD.ConclusionSNPs (rs924080 and rs11209032) of the IL23R-IL12RB2 region were found to be associated with BD in a Northern Chinese Han population.     

Genetic polymorphisms of interleukin-6 gene and susceptibility to coronary artery disease in Chinese population: Evidence based on 4582 subjects

The aim of this study was to explore whether interleukin-6 (IL-6) gene (−174 G/C and −572 C/G) polymorphisms are associated with susceptibility to coronary artery disease (CAD) risk in Chinese population. All the statistical tests were performed using Stata version 11.0. Twelve articles involving 16 studies were included in this meta-analysis, covering a total of 2309 CAD cases and 2273 controls. For IL-6 gene −572 C/G polymorphism, the results showed evidence for significant association between IL-6 gene −572 C/G polymorphism and CAD risk (for G allele vs. C allele: OR = 1.48, 95% CI = 1.26–1.74, p < 0.001; for G/G vs. C/C: OR = 2.60, 95% CI = 1.54–4.39, p < 0.001; for G/G vs. G/C + C/C: OR = 2.15, 95% CI = 1.35–3.42, p = 0.001; for G/G + G/C vs. C/C: OR = 1.55, 95% CI = 1.29–1.85, p < 0.001). However, for IL-6 gene −174 G/C polymorphism, no significant association was found between this variation and CAD risk. In summary, our meta-analysis showed evidence that IL-6 gene −572 C/G polymorphism may be a risk factor for CAD susceptibility. For IL-6 gene −174 G/C polymorphism, no significant association was found between this variation and CAD risk.     

CD38 gene polymorphisms and genetic predisposition to multiple myeloma

Single nucleotide polymorphisms (SNPs) of adhesion and signaling genes may influence the etiopathogenesis of multiple myeloma (MM). CD38 molecule and its ligand CD31 are expressed and interact in malignant plasma cells and MM microenvironment. In this study we evaluated allele frequencies and distribution of two potentially functional CD38 SNPs, intronic rs6449182 (184C>G) and missense rs1800561 (418C>T, Arg¹⁴⁰Trp) in 175 Caucasian patients with MM and 207 healthy blood donors. The carriers of variant G allele of the rs6449182 SNPs were found to have significantly elevated risk of MM as compared to non-carriers; odds ratio = 5.69 (95% confidence interval = 3.7–8.7), p < 0.0001. In contrast, rs1800561 SNP minor T allele was detected at very low and comparable frequencies in patients and controls groups. In conclusion, our data suggest that inherited genetic variation in CD38 gene may impact on the risk of MM development.     

Is the ABCB1 Gene Associated with the Increased Risk of Gastric Cancer Development?—Preliminary Research

One of the most common malignant diseases, both worldwide and in Poland, is gastric cancer. The pathogenesis of gastric cancer development is not entirely clear. Next to the environmental risk factors, such as Helicobacter pylori infection or dietary habits, the host genetic factors as predispositions to gastric cancer development are discussed. A transmembrane protein that could be associated with predisposition to cancer development is P-glycoprotein (P-gp). Physiologically, P-gp is present in normal tissue of the gastrointestinal tract, where it plays a protective role by transporting xenobiotics from a cell into extracellular environment. P-gp is encoded by the highly polymorphic ABCB1 gene. The most frequent polymorphisms at positions 1236, 2677, and 3435 may affect both the function and amount of protein, thereby leading to a loss of its physiological function, which could increase the predisposition to development of many diseases, including cancer. In this study, the potential significance of the ABCB1 gene in the development and progression of gastric cancer was evaluated.In 19 tissue samples collected from patients with gastric cancer, the ABCB1 gene polymorphisms were identified at positions 1236 and 2677 by automated sequencing and SNP 3435 by the RFLP method. The relative level of ABCB1 expression was measured in 10 samples of gastric cancer and morphologically normal tissues by real-time PCR.For SNPs at positions 1236, 2677, and 3435, no statistically significant differences in genotype frequencies between gastric cancer patients and healthy individuals were found. However, genotype TT for all studied polymorphisms occurred more frequently in the group of gastric cancer patients (31.6, 26.3, 42.1%, respectively) than in the group of healthy individuals (14.6, 13.5, 21.9%, respectively). The lowest relative expression levels of ABCB1 mRNA were observed for genotypes CC of SNP 1236, CC of SNP 3435, and GG of SNP 2677 (median: 0.215, 0.160, 0.160, respectively). There was a tendency that mutant homozygote TT for SNPs at positions 1236, 2677, and 3435 occurred more frequently in the subgroup of patients with Tis or stage I of TNM classification (SNP 1236 p = 0.0760; SNP 2677 p = 0.0813; SNP 3435 p = 0.0760) than in the subgroup of patients with stage II or III. Also the expression levels were lowest (median 0.740) in the group of patients with the less advanced clinical stage of cancer (Tis or I).Preliminary research showed that the ABCB1 gene polymorphisms at positions 1236, 2677, and 3435 were not related to an increased susceptibility of gastric cancer development. However, they may be associated with the inhibition of gastric cancer progression.