Association of Signal Transducer and Activator of Transcription 3 Gene Polymorphisms with Cervical Cancer in Chinese Women

Vaginal Microbiota and HPV in Latin America: A Narrative Review

With the expansion of human microbiome studies in the last 15 years, we have realized the immense implications of microbes in human health. The human holobiont is now accepted, given the commensal relationships with bacteria, fungi, parasites, viruses, and human cells. The cervicovaginal microbiota is a specific case within the human microbiome where diversity is lower to maintain a chemical barrier of protection against infections. This narrative review focuses on the vaginal microbiome. It summarizes key findings on how native bacteria protect women from disease or predispose them to damaging inflammatory processes with an emphasis on the role of HPV infections in Latin America, one of the world's regions with the highest cervical cancer prevalence.

Association of JAK/STAT genetic variants with cutaneous melanoma

Background

The Janus-activated kinase (JAK)-signal transducer and activator of transcription (STAT) signaling pathway regulates cutaneous melanoma (CM) development and progression. The JAK1, JAK2, and STAT3 proteins are encoded by polymorphic genes. This study aimed to verify whether single-nucleotide variants (SNVs) in JAK1 (c.1648+1272G>A, c.991-27C>T), JAK2 (c.-1132G>T, c.-139G>A), and STAT3 (c.*1671T>C, c.-1937C>G) altered the risk, clinicopathological aspects, and survival of CM patients as well as protein activity.

Methods

CM patients (N = 248) and controls (N = 274) were enrolled in this study. Genotyping was performed by real-time polymerase chain reaction (PCR), and JAK1, JAK2, and STAT3 expression was assessed by quantitative PCR (qPCR). STAT3 c.-1937C>G SNV was investigated by luciferase, qPCR, western blot, apoptosis, and cell cycle assays in SKMEL-28 cells with CC or GG genotype.

Results

Individuals with STAT3 c.*1671TT and c.-1937CC genotypes and TC haplotype of both SNVs were under about 2.0-fold increased risk of CM. Specific JAK1, JAK2, and STAT3 combined genotypes were associated with up to 4.0-fold increased risk of CM. Higher luciferase activity [4,013.34 vs. 2,463.32 arbitrary units (AU); p = 0.004], STAT3 expression by qPCR (649.20 vs. 0.03 AU; p = 0.003) and western blot (1.69 vs. 1.16 AU; p = 0.01), and percentage of cells in the S phase of the cell cycle (57.54 vs. 30.73%; p = 0.04) were more frequent in SKMEL-28 with STAT3 c.-1937CC than with GG genotype. CM cell line with CC genotype presented higher STAT3 protein levels than the one with GG genotype (1.93 versus 1.27 AU, p = 0.0027).

Conclusion

Our data present preliminary evidence that inherited abnormalities in the JAK/STAT pathway can be used to identify individuals at a high risk of CM, who deserve additional attention for tumor prevention and early detection.

Prioritization and Meta-analysis of regulatory SNPs identified IL6, TGFB1, TLR9 and MMP7 as significantly associated with cervical cancer

Cervical cancer is a leading women cancer globally with respect to both incidence and mortality. Its increased risk has been linked with HPV infection and genetic variations like single nucleotide polymorphisms (SNPs). Although, studies have been published which evaluates the effect of SNPs in a few candidate genes, however the role of number of regulatory SNPs (rSNPs) in cervical cancer is not available. As literature evidence has shown that non-coding rSNPs are related with increasing cervical cancer risk, we undertook this study to prioritize the important rSNPs and elucidate their role. A search was conducted in PubMed up to December 2020, which led to the identification of 263 articles and 969 SNPs in the non-coding region. These 969 SNPs were analysed through rSNPBase and RegulomeDB, leading to identification of 105 rSNPs. Afterwards, a regulatory module was constructed using protein-protein interaction data and a hub of highly interacting 23 target genes (corresponding to 34 rSNPs) was identified using MCODE. To further understand the mechanism of action of the 34 rSNPs, their transcription factor information with respect to cervical cancer was retrieved. To evaluate the pooled effect of these prioritized polymorphisms in cervical cancer patients, a meta-analysis was performed on 10,537 cases and 11,252 controls from 30 studies corresponding to 8 rSNPs. It led to identification of polymorphisms in IL6 (rs2069837), TGFB1 (rs1800469), TLR9 (rs187084) and MMP7 (rs11568818) which are significantly (p < 0.05) associated with increased cervical cancer risk at the population level. Overall, the study demonstrates that rSNPs targeting immune and inflammatory genes (IL1B, IL6, IL10, IL18, TGFB1, CCR5, CD40, TLR9, and MMP7) are associated with cervical cancer.

STAT3 polymorphisms in North Africa and its implication in breast cancer

BACKGROUND

Only a few studies have investigated the association of single nucleotide polymorphisms in STAT3 gene with the susceptibility to cancer and response to chemotherapy. Our aim was to determine the allele frequencies of rs3869550, rs957971, and rs7211777 at the STAT3 gene in North African populations and compare them to 1000 genomes populations, and to investigate their relation with cancer.

METHODS

The targeted SNPs have been analyzed in six Tunisian populations and a sample of Libyans using TaqMan® Assay. The results were compared to 1000 Genomes Project population samples. Targeting of the regions encompassing the three SNPs by micro-ARN was assessed using miR databases.

RESULTS

The analysis of the 3 SNPs showed that North African populations were close to South Asians. As expected, African populations presented a significant frequency of the ancestral CCG haplotype in contrast to other populations where the fully derived TGA haplotype was more frequent. The presence and diversity of rare haplotypes at STAT3 in North African populations could have been generated by recombination between the two major haplotypes. A screening of the micro-RNA databases showed that the STAT3 region with the mutated allele of rs7211777 (G>A) could be targeted by miR hsa-miR-3606-5p, which also targets genes involved in breast cancer.

The polymorphisms of IL-6/STAT3 signaling pathway may contribute to cutaneous T-cell lymphomas susceptibility

IL-6/STAT3 signaling pathway has been suggested to play a role in CTCL pathogenesis. Polymorphisms in STAT3 signaling pathway-related genes might be a risk factor for CTCL. However, the exact role of inherited gene polymorphisms of IL-6 and STAT3 in the pathogenesis of CTCL is still not fully understood. The aim was to examine whether IL-6 cytokine and polymorphisms of IL-6 and STAT3 gene are associated with CTCL susceptibility, stage of disease and pruritus intensity. We compared the IL-6 serum level and the frequency of selected single nucleotide polymorphisms of IL-6 and STAT3 in 106 CTCL and 198 control group using polymerase chain reaction with sequence-specific primers method and ELISA. We have found that serum IL-6 level in CTCL patients was significantly higher than in healthy controls (p < 0.05). We also demonstrated that two genotypes, CC of IL-6 and GG of STAT3, were overexpressed in CTCL patients compared to healthy controls, and that they increase the risk of malignancy development (OR = 1.8, p = 0.04 for IL-6 and OR 2.53, p = 0.0064 for STAT3). Moreover, the GG genotype of STAT3 polymorphism seems to be associated with lack of pruritus or mild pruritus in CTCL patients. Our results indicate that IL-6 is involved in pathogenesis of CTCL but not pruritus. Moreover, CC of IL-6 and GG genotype of STAT3 genes might be considered as the risk factor for development of CTCL.

STAT3 polymorphisms and IL-6 polymorphism are associated with the risk of basal cell carcinoma in patients from northern Poland

Basal cell carcinoma (BCC) environment consists of stromal and inflammatory cells which produce variety of cytokines, chemokines and growth factors that may affect tumor behavior. One of the cytokines suggested to be involved in the pathogenesis of BCC is IL-6, which is the upstream element of IL-6/JAK/STAT3 pathway. The correlation between polymorphisms of the genes related to this pathway and cancer risk/prognosis have been previously investigated in several neoplasia, but available data concerning BCC are scarce. In the present study, rs1800795 (-174 G/C) IL-6 gene polymorphism and two polymorphisms in the STAT3 gene, namely rs2293152 (intron 11, C/G) and rs4796793 (-1697, C/G) were assessed in relation to the BCC risk and clinical course. Additionally, IL-6 serum level was assessed in relation to IL-6 genotype and clinical variables. The study included 254 unrelated patients with BCC and of mean age 70.39 ± 11.43 (69.83 ± 12.32 women, 71.03 ± 10.31 men) and 198 healthy, unrelated age- and sex-matched volunteers. IL-6 and STAT3 polymorphisms were analyzed using polymerase chain reaction with sequence-specific primers (SSP-PCR). Serum concentration of IL-6 was measured using the ELISA test. We have found that the presence of C allele in rs1800795 IL-6 gene polymorphism was associated with increased risk of BCC (aOR 1.86; 95% CI 1.22–2.84; p = 0.004). The presence of CC genotype in STAT3 rs2293152 polymorphism was associated with increased BCC risk in recessive model analysis (aOR 3.94; 95% CI 1.59–9.77; p = 0.003). In contrast, the presence of GC genotype in overdominant model was associated with decreased risk of BCC (aOR = 0.24; 95% CI 0.12–0.49; p < 0.0001). The presence of C allele in STAT3 rs2293152 polymorphism was associated with increased risk of BCC (aOR 1.31; 95% CI 1.01–1.69; p = 0.04). The presence of GG genotype in STAT3 rs4796793 polymorphism was associated with increased BCC risk in recessive model analysis (aOR 3.66; 95% CI 1.33–10.10; p = 0.012). The presence of G allele in STAT3 rs4796793 polymorphism was associated with increased risk of BCC (aOR 1.59; 95% CI 1.01–2.49; p = 0.04). IL-6 serum level positively correlated with the tumor size.

Influence of STAT4 gene polymorphisms in the pathogenesis of endometriosis

The STAT4 gene is vital to signaling pathways in the immune response. Immunological alterations are involved in the pathogenesis of endometriosis, and STAT4 polymorphisms may be linked to disease development. This study's aim is to evaluate the possible association between four STAT4 polymorphisms (rs7601754/G > A, rs11889341/C > T, rs7574865/T > G, and rs7582694/C > G) and the pathogenesis of endometriosis in Brazilian women. This case-control study's sample comprised 238 women with endometriosis and 201 healthy, fertile women without endometriosis (which was surgically confirmed). Genotyping was performed using the TaqMan system with a real-time polymerase chain reaction; the genotype, allele, and haplotype frequencies were then compared between groups. A single-polymorphism analysis revealed that the TT genotype of the rs7574865/T > G polymorphism was significantly more frequent in women with minimal or mild endometriosis than in the controls (10% vs. 5%, p = 0.047). The CGAC, GTAT, and GTAC haplotypes were significantly more frequent in the women with endometriosis-related infertility (5.8%, 4.1%, and 2.9%, respectively) than in the controls (2.4%, 1.1%, and 0.8%, respectively; p = 0.020, p = 0.011, and p = 0.032, respectively), but the GGGC and CTAT haplotypes were significantly more prevalent in the control group (34.7% and 13.9%, respectively) than among the infertile group (26.2% and 9.1%, respectively). In addition, the CGAC haplotype was more frequently found in those with minimal or mild endometriosis (6.8%) than in the controls (2.4%, p = 0.009), and the GTAT haplotype was more commonly found in those with moderate or severe disease (3.6%) than in the controls (1.1%, p = 0.028). These findings suggest that STAT4 polymorphisms can influence the pathogenesis of endometriosis.

Interleukin-21 receptor gene polymorphism is associated with hepatitis B virus-related hepatocellular carcinoma in Chinese patients

Background

We investigated the relationship between hepatitis B virus (HBV)‐related pathogenesis and single nucleotide polymorphisms (SNPs) in interleukin‐21 (IL‐21)‐JAK‐STAT signaling pathway genes.

Methods

We used the high‐resolution melting (HRM) method to genotype five SNPs (IL‐21 rs2221903, IL‐21 rs4833837, IL‐21 receptor (IL‐21R) rs2285452, JAK3 rs3008, and STAT3 rs1053023) in 546 HBV‐infected patients and 353 healthy Chinese subjects. The HBV‐infected patients were further divided into subgroups based on the HBV‐related pathologies: chronic hepatitis B (CHB), HBV‐related liver cirrhosis (LC), and HBV‐related hepatocellular carcinoma (HCC).

Results

There were no significant differences in the genotype and allele distributions of the five SNPs between the HBV‐infected patients and healthy subjects. The genotype and allele frequencies were similar in the two groups for IL‐21 rs2221903 (A>G, P = 0.83 and 0.67), rs4833837 (A>G, P = 0.80 and 0.49), IL‐21R rs2285452 (G>A, P = 0.25 and 0.68), STAT3 rs1053023 (A>G, P = 1.00 and 0.96), and JAK3 rs3008 (C>T, P = 0.32 and 0.54). However, patients with the IL‐21R rs2285452 AA genotype were more susceptible to HBV‐related HCC than those with the IL‐21R rs2285452 GA/GG genotype (P = 0.03, OR = 3.27, 95% CI = 1.16‐9.20). The serological marker model of “HBsAg+, HBeAg+, HBcAb+” was predominant among patients with HBV infection. However, there was no association between the genotype's distribution of the five SNPs and the serological marker models (P > 0.05).

Conclusions

These findings demonstrate that the IL‐21R rs2285452 AA genotype increases the risk of HBV‐related HCC in Chinese patients.

STAT3 rs4796793 contributes to lung cancer risk and clinical outcomes of platinum-based chemotherapy

BACKGROUND

Signal transducer and activator of transcription (STAT) 3 plays a vital role in carcinogenesis and drug response. Platinum-based chemotherapy is the first-line treatment for lung cancer patients, especially those in advanced stages. In the present study, we investigated the association of STAT3 polymorphism rs4796793 with lung cancer susceptibility, platinum-based chemotherapy response, and toxicity.

METHODS

A total of 498 lung cancer patients and 213 healthy controls were enrolled in the study. 467 of them received at least 2-cycle platinum-based chemotherapy. Unconditional logistical regression analysis was used to assess the associations.

RESULTS

STAT3 rs4769793 G allele carriers had an increased susceptibility of lung cancer [additive model: adjusted OR (95% CI) 1.376 (1.058-1.789), P = 0.017; recessive model: adjusted OR (95% CI) 1.734 (1.007-2.985), P = 0.047]. Rs4769793 was not significantly associated with platinum-based chemotherapy response in lung cancer patients. STAT3 rs4796793 was associated with an increased risk of severe overall toxicity [additive model: adjusted OR (95% CI) 1.410 (1.076-1.850), P = 0.013; dominant model: adjusted OR (95% CI) 1.638 (1.091-2.459), P = 0.017], especially hematological toxicity [additive model: adjusted OR (95% CI) 1.352 (1.001-1.826), P = 0.049].

CONCLUSIONS

STAT3 rs4796793 may be considered as a potential candidate biomarker for the prediction of susceptibility and prognosis in Chinese lung cancer patients. However, well-designed studies with larger sample sizes are required to verify the results.

Association of Single Nucleotide Polymorphism rs1053004 in Signal Transducer and Activator of Transcription 3 (STAT3) with Susceptibility to Hepatocellular Carcinoma in Thai Patients with Chronic Hepatitis B

The single nucleotide polymorphism (SNP) rs1053004 in Signal transducer and activator of transcription 3 (STAT3) was recently reported to be associated with chronic hepatitis B (CHB)-related hepatocellular carcinoma (HCC) in a Chinese cohort. This study was aimed at investigating whether the SNP might also contribute to HCC susceptibility in the Thai population. Study subjects were enrolled and divided into 3 groups including CHB-related HCC (n=211), CHB without HCC (n=233) and healthy controls (n=206). The SNP was genotyped using allelic discrimination assays based on TaqMan real-time PCR. Data analysis revealed that the distribution of different genotypes was in Hardy-Weinberg equilibrium (P>0.05). The frequencies of allele T (major allele) in HCC patients, CHB patients and healthy controls were 51.4%, 58.6% and 61.4%, respectively, whereas the frequencies of C allele (minor allele) were 48.6%, 41.4% and 38.6%. The C allele frequency was higher in HCC when compared with CHB patients (odds ratio (OR)=1.34, 95% confidence interval (CI)=1.02-1.74, P=0.032). The genotype of SNP rs1053004 (CC versus TT+TC) was significantly associated with an increased risk when compared with CHB patients (OR=1.83, 95% CI=1.13-2.99, P=0.015). In addition, we observed a similar trend of association when comparing HCC patients with healthy controls (OR=1.77, 95% CI=1.07-2.93, P=0.025) and all controls (OR=1.81, 95% CI=1.19-2.74, P=0.005). These findings suggest that the SNP rs1053004 in STAT3 might contribute to HCC susceptibility and could be used as a genetic marker for HCC in the Thai population.

Association between STAT3 polymorphisms and cancer risk: a meta-analysis

Five polymorphisms, rs2293152, rs4796793, rs12949918, rs6503695, rs744166, in the STAT3 gene have been implicated in susceptibility to cancer, but the results were inconclusive. The aim of this meta-analysis is to investigate the association between the five polymorphisms and cancer risk. All eligible case-control studies published up to March 2015 were identified by searching PubMed, Web of Science, Wanfang, VIP, and CNKI. Effect sizes of odds ratio (OR) and 95 % confidence interval (95 % CI) were calculated by using a fixed- or random-effect model. A total of 15 articles were included. Overall, a significantly decreased risk was found for rs12949918 polymorphism (dominant model: OR = 0.83, 95 % CI: 0.75-0.91, recessive model: OR = 0.77, 95 % CI: 0.68-0.87, TC vs. TT: OR = 0.87, 95 % CI: 0.79-0.96, CC vs. TT: OR = 0.71, 95 % CI: 0.62-0.81), and for rs744166 polymorphism (recessive model: OR = 0.75, 95 % CI: 0.58-0.98; GG vs. AA: OR = 0.68, 95 % CI: 0.51-0.90), while there was no significant association for other three polymorphisms under all genetic models. In subgroup analysis by ethnicity, for rs12949918 polymorphism, similar results were detected among Caucasians, similarly, a significant decreased risk was observed in Asians under dominant and CC vs. TT model; for rs2293152 polymorphism, significant association was detected among Asians under recessive model. This meta-analysis suggests that the STAT3 rs12949918 and rs744166 polymorphisms, but not other three polymorphisms, may be an important protective factor for cancer.

Association Study of Single-Nucleotide Polymorphisms of STAT2/STAT3/IFN-γ Genes in Cervical Cancer in Southern Chinese Han Women

OBJECTIVE

Interferon-γ (IFN-γ) and signal transducers and activators of transcription (STATs) each play an important role in carcinogenesis associated with viral infection. Cervical cancer is almost invariably associated with infection by human papillomavirus (HPV), and previous studies suggested that dysregulation of the signal pathway involved in IFN-γ and STATs is associated. Our objective was to evaluate the association of SNPs in STAT2, STAT3, and IFN-γ with cervical cancer susceptibility in Chinese Han women in Hunan province.

MATERIALS AND METHODS

Genomic DNA was extracted from peripheral blood samples of 234 cervical cancer patients and 216 healthy female controls. STAT2 and STAT3 genotyping was performed using polymerase chain reaction-restriction enzyme (PCR-RE) analysis. IFN-γ genotyping was detected by PCR-amplification of specific allele (PASA).

RESULTS

For STAT2 rs2066807 polymorphisms, there was no significant difference of genotype distribution (P=0.827) and allele frequencies (P=0.830, OR=1.09, 95% CI: 0.51-2.31) between cases and controls. For STAT3 rs957970 polymorphisms, there was no significant difference of genotype distribution (P=0.455) and allele frequencies (P=0.560, OR=0.92, 95% CI: 0.71-1.20) between cases and controls. For IFN-γ +874A/T polymorphisms, there was no significant difference of genotype distribution (P=0.652) and allele frequencies (P=0.527, OR=1.12, 95% CI: 0.79-1.59) between cases and controls.

CONCLUSION

These results suggest that polymorphisms in STAT2, STAT3 and IFN-γ genes are not likely to be strong predictors of cervical cancer in Han women in southern China.

STAT3 genetic variant, alone and in combination with STAT5b polymorphism, contributes to breast cancer risk and clinical outcomes

The genetic or abnormal activation of signal transducer and activator of transcription (STATs) family proteins play an important role with regard to disease progression in variety of human malignancies, yet no data are available for candidate gene and breast cancer (BC) risk. To address this, we investigate the correlation between STAT3, STAT5b polymorphisms and BC susceptibility, clinicopathological parameters, and clinical outcomes. A case-control study was carried out in 1,240 BC patients and 882 healthy controls using TaqMan assay and PCR-RFLP method. A significant decreased risk of BC was associated with STAT3 G allele and combined effect (validation alleles). Furthermore, patients after anthracycline-based chemotherapy, carrying combined effect of STAT3 rs4796793 and STAT5b rs6503691, had significantly increased progression-free survival (PFS) [adjusted HR (95 % CI) 0.831 (0.704-0.980), P = 0.028]. More importantly, ER-negative patients with STAT5b CT/TT genotype was associated with a longer PFS [adjusted HR (95 % CI) 0.519 (0.293-0.920), P = 0.025], recurrence-free survival [adjusted HR (95 % CI) 0.529 (0.298-0.939), P = 0.030], and overall survival [adjusted HR (95 % CI) 0.547 (0.308-0.973), P = 0.040]. These results indicated that STAT3 and STAT5b polymorphisms might be a candidate pharmacogenomic factor to assess susceptibility and prognosis in BC patients.

Lessons and implications from association studies and post-GWAS analyses of cervical cancer

Cervical cancer has a heritable genetic component. A large number of genetic associations with cervical cancer have been reported in hypothesis-driven candidate gene studies, but many of these results are either inconsistent or have failed to be independently replicated. Genome-wide association studies (GWAS) have identified additional susceptibility loci previously not implicated in cervical cancer development, highlighting the power of genome-wide unbiased association analyses. Post-GWAS analyses including pathway-based analysis and functional characterization of associated variants have provided new insights into the pathogenesis of cervical cancer. In this review we summarize findings from candidate gene association studies, GWAS, and post-GWAS analyses of cervical cancer. We also discuss gaps in our understanding, possible clinical implications of the findings, and lessons for studies of other complex diseases.

rs744166 polymorphism of the STAT3 gene is associated with risk of gastric cancer in a Chinese population

The aim of this study was to explore the association between polymorphisms in signal transducer and activator of transcription protein 3 (STAT3) and the risk of gastric cancer. In the present study, a case-control study was conducted in which rs2293152 and rs744166 polymorphisms in STAT3 were analyzed in 209 Chinese patients with gastric cancer and 294 cancer-free controls. The genotypes were determined by polymerase chain reaction restriction fragment length polymorphism method. For the rs744166 polymorphism, the TC genotype (adjusted OR = 0.60, 95% CI = 0.39-0.92, and P = 0.020) and CC genotype (adjusted OR = 0.41, 95% CI = 0.21-0.80, and P = 0.009) were associated with a decreased risk of gastric cancer compared to the TT genotype. However, rs2293152 did not show any difference in gastric cancer risk between patients and controls in the CG/CC genotype compared to the GG genotype. Besides, the SNP effects were additive to the effects of environmental factors without any interaction between them in the susceptibility to gastric cancer. Collectively, rs744166 polymorphism might be significantly associated with a decreased risk of gastric cancer in a Chinese population. Additionally, polymorphisms in STAT3, along with environmental factors, might be associated with the development of gastric cancer.

Stat3 induces oncogenic Skp2 expression in human cervical carcinoma cells

Dysregulated Skp2 function promotes cell proliferation, which is consistent with observations of Skp2 over-expression in many types of human cancers, including cervical carcinoma (CC). However, the molecular mechanisms underlying elevated Skp2 expression have not been fully explored. Interleukin-6 (IL-6) induced Stat3 activation is viewed as crucial for multiple tumor growth and metastasis. Here, we demonstrate that Skp2 is a direct transcriptional target of Stat3 in the human cervical carcinoma cells. Our data show that IL-6 administration or transfection of a constitutively activated Stat3 in HeLa cells activates Skp2 mRNA transcription. Using luciferase reporter and ChIP assays, we show that Stat3 binds to the promoter region of Skp2 and promotes its activity through recruiting P300. As a result of the increase of Skp2 expression, endogenous p27 protein levels are markedly decreased. Thus, our results suggest a previously unknown Stat3-Skp2 molecular network controlling cervical carcinoma development.

Association between polymorphisms in the signal transducer and activator of transcription and dilated cardiomyopathy in the Chinese Han population

The signal transduction pathways mediating the progress of heart failure have been intensively studied. Altered signaling of the signal transducers and activators of transcription (STATs), which play important roles in regulating cell proliferation, differentiation, and apoptosis, has been observed in the heart. We conducted a pilot study to test whether single nucleotide polymorphisms (SNPs) in STATs were associated with dilated cardiomyopathy (DCM). Genotypes of two SNPs of STATs (rs6503691 C/T in exon 1 of STAT5B and rs4796793 C/G in the 5' region of STAT3) in 251 DCM patients and 484 control subjects were determined with the use of PCR-restriction fragment length polymorphism assay and TaqMan assay, respectively. Significantly increased DCM risk was found to be associated with T allele of rs6503691 (P = 0.012, OR = 1.37, 95% CI = 1.07-1.74). We found that increased DCM risk statistically significantly associated with rs6503691 in a dominant model (P = 0.009, OR = 1.50, 95% CI = 1.11-2.04). No association between DCM risk and rs4796793 was observed (P = 0.706, OR = 1.05, 95% CI = 0.83-1.32). The present pilot study provides evidence that both rs6503691 T allele and CT/TT genotypes, but not rs4796793 C/G in the 5' region of STAT3, are associated with a significantly increased risk of DCM, indicating that common genetic polymorphism in STATs is associated with DCM.