Association between the Cytotoxic T-lymphocyte antigen 4 +49G > A polymorphism and cancer risk: a meta-analysis

Functional analysis of CTLA4 promoter variant and its possible implication in colorectal cancer immunotherapy

Background

Colorectal cancer (CRC) is a prevalent cancer, ranking as the third most common. Recent advances in our understanding of the molecular causes of this disease have highlighted the crucial role of tumor immune evasion in its initiation and progression. CTLA4, a receptor that acts as a negative regulator of T cell responses, plays a pivotal role in this process, and genetic variations in CTLA4 have been linked to CRC susceptibility, prognosis, and response to therapy.

Methods

We conducted a case-control study involving 98 CRC patients and 424 controls. We genotyped the CTLA4 c.-319C > T variant (rs5742909) and performed an association analysis by comparing allele frequencies between the patients and controls. To assess the potential functional impact of this variant, we first performed an In Silico analysis of transcription factor binding sites using Genomatix. Finally, to validate our findings, we conducted a luciferase reporter gene assay using different cell lines and an electrophoretic mobility shift assay (EMSA).

Results

The case-control association analysis revealed a significant association between CTLA4 c.-319C > T and CRC susceptibility (p = 0.023; OR 1.89; 95% CI = 1.11-3.23). Genomatix analysis identified LEF1 and TCF7 transcription factors as specific binders to CTLA4 c.-319C. The reporter gene assay demonstrated notable differences in luciferase activity between the c.-319 C and T alleles in COS-7, HCT116, and Jurkat cell lines. EMSA analysis showed differences in TCF7 interaction with the CTLA4 C and T alleles.

Conclusion

CTLA4 c.-319C > T is associated with CRC susceptibility. Based on our functional validation results, we proposed that CTLA4 c.-319C > T alters gene expression at the transcriptional level, triggering a stronger negative regulation of T-cells and immune tumoral evasion.

Evidence of Association between CTLA-4 Gene Polymorphisms and Colorectal Cancers in Saudi Patients

Cytotoxic T lymphocyte antigen-4 (CTLA-4) has been identified as an immunosuppressive molecule involved in the negative regulation of T cells. It is highly expressed in several types of autoimmune diseases and cancers including colorectal cancer (CRC). (1) Objective: To explore the association between CTLA-4 single nucleotide polymorphisms (SNP) and risk to (CRC) in the Saudi population. (2) Methods: In this case-control study, 100 patients with CRC and 100 matched healthy controls were genotyped for three CTLA-4 SNPs: rs11571317 (-658C > T), rs231775 (+49A > G) and rs3087243 (CT60 G > A), using TaqMan assay method. Associations were evaluated using odds ratios (ORs) and 95% confidence intervals (95% CIs) for five inheritance models (co-dominant, dominant, recessive, over-dominant and log-additive). Furthermore, CTLA-4 expression levels were evaluated using quantitative real-time PCR (Q-RT-PCR) in colon cancer and adjacent colon tissues. (3) Results: Our result showed a significant association of the G allele (OR = 2.337, p < 0.0001) and GG genotype of the missense SNP +49A > G with increased risk of developing CRC in codominant (OR = 8.93, p < 0.0001) and recessive (OR = 16.32, p < 0.0001) models. Inversely, the AG genotype was significantly associated with decreased risk to CRC in the codominant model (OR = 0.23, p < 0.0001). In addition, the CT60 G > A polymorphism exhibited a strong association with a high risk of developing CRC for the AA genotype in codominant (OR = 3.323, p = 0.0053) and in allele models (OR = 1.816, p = 0.005). No significant association was found between -658C > T and CRC. The haplotype analysis showed that the G-A-G haplotype of the rs11571317, rs231775 and rs3087243 was associated with high risk for CRC (OR = 57.66; p < 0.001). The CTLA-4 mRNA gene expression was found significantly higher in tumors compared to normal adjacent colon samples (p < 0.001). (4) Conclusions: Our findings support an association between the CTLA-4 rs231775 (+49A > G) and rs3087243 (CT60 G > A) polymorphisms and CRC risk in the Saudi population. Further validation in a larger cohort size is needed prior to utilizing these SNPs as a potential screening marker in the Saudi population.

Umbilical cord blood transplantation and the impact of the CTLA4 genotype on outcomes

Background: Umbilical cord blood transplantation is an effective method of curing multiple diseases when there is no donor available for allogeneic hematopoietic stem cell transplantation (AHSCT). It has been recently suggested that polymorphisms in genes affecting antigen presentation could potentially affect cord blood transplantation (CBT) outcomes.Areas covered: In this review, we present the results of the latest studies investigating the link between CTLA4 gene variability and umbilical cord blood transplantation outcomes.Expert opinion: The search for genetic variants that influence the immune response, both innate and adaptive immunity, may lead to more optimal therapies. Promising candidate genes are those that regulate the expression of proteins associated with T-cell activation. Many genetic variants could be therapeutically important, including those related to innate and adaptive immunity, cytokines, chemokines, drug-metabolizing enzymes, drug transporters, and inflammatory enzymes. The development of an algorithm that includes the determination of selected genetic variants could be helpful for an appropriate donor-recipient CBT matching.

CTLA4 antagonists in phase I and phase II clinical trials, current status and future perspectives for cancer therapy

INTRODUCTION

In cancer, the immune response to tumor antigens is often suppressed by inhibitors and ligands. Checkpoint blockade, considered one of the most promising frontiers for anti-cancer therapy, aims to stimulate the immune anti-cancer response. Agents such as cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) inhibitors offer prolonged survival with manageable side effects.

AREAS COVERED

We summarize the recent clinical successes of CTLA-4 inhibitors and place a strong emphasis on those in early phase clinical trials, often in combination with other immune check-point inhibitors, i.e., programmed cell death protein 1 (PD-1) and BRAF/mitogen-activated protein kinase inhibitors.

EXPERT OPINION

Recent phase I and phase II clinical trials confirm the efficacy of anti-CTLA-4 therapy for treatment of cancers such as renal cell carcinoma. These studies also indicated increased efficacy with combined immune checkpoint blockade with PD-1 or Ras/Raf/mitogen-activated protein kinase/ERK kinase (MEK)/extracellular-signal-regulated kinase (ERK) inhibitors. Researchers must search for new immune targets that may enable more effective and safe immune checkpoint blockade and cancer therapy. This goal may be achieved by next-generation combination therapies to overcome immune checkpoint therapy resistance.

CTLA4 tagging polymorphisms and risk of colorectal cancer: a case-control study involving 2,306 subjects

Background

CTLA4 is a candidate gene which has been implicated in the development of colorectal cancer (CRC).

Patients and Methods

To determine the important role of CTLA-4 polymorphisms on risk of CRC, we genotyped four CTLA-4 tagging polymorphisms and calculated crude/adjusted ORs with their 95% CIs. We recruited 1,003 sporadic CRC cases and 1,303 controls.

Results

The findings suggested that CTLA-4 rs231775 G>A polymorphism increased the risk of CRC (homozygote model: adjusted OR=1.40, 95% CI=1.05-1.87, P=0.022; dominant model: adjusted OR=1.19, 95% CI=1.00-1.41, P=0.047; and recessive model: adjusted OR=1.38, 95% CI=1.05-1.82, P=0.021). In a stratified analysis by site of tumor, this association was also found in colon cancer. We also found that CTLA-4 rs231775 GA/AA genotypes might be associated with an increased risk of CRC in Zhenjiang cohort. In addition, we found the CTLA-4 rs16840252 C>T polymorphism was associated with the risk of colon cancer. Haplotype comparison analysis showed that CTLA-4 G_rs3087243C_rs16840252C_rs733618 A_rs231775, G_rs3087243C_rs16840252T_rs733618A_rs231775, and other haplotypes increased the risk of CRC (P<0.001, <0.001, and 0.002, respectively).

Conclusion

This study evidences an association of CTLA-4 tagging polymorphisms and haplotypes with CRC risk. Additional well-designed studies with large sample sizes are required to confirm our findings.

Investigation of Cytotoxic T-lymphocyte antigen 4 Polymorphisms in Gastric Cardia Adenocarcinoma

To assess the potential effects of Cytotoxic T-lymphocyte antigen 4 (CTLA4) gene polymorphisms on susceptibility to gastric cardia adenocarcinoma (GCA), we genotyped four polymorphisms (rs733618 A>G, rs16840252 C>T, rs231775 G>A and rs3087243 G>A) in CTLA4 and calculated odds ratios (ORs) with the corresponding 95% confidence intervals (95% CIs) for the genotype and allele distributions between GCA cases and controls. The CTLA4 genotypes were determined by the polymerase chain reaction-ligase detection reaction (PCR-LDR) analysis in 330 GCA patients and 608 unrelated cancer-free controls. In this case-control study, there was no significant difference in the genotype and allele distributions of four CTLA4 polymorphisms between GCA patients and controls. However, haplotype association analysis indicated that compared with CTLA4 Grs733618 Crs16840252 Grs231775 Crs3087243 , CTLA4 Grs733618 Crs16840252 Ars231775 Grs3087243 and Ars733618 Crs16840252 Grs231775 Ars3087243 haplotypes conferred increased risks of GCA (OR = 6.46, 95% CI = 1.33-31.28; P = 0.012; both); however, CTLA4 Ars733618 Crs16840252 Ars231775 Grs3087243 and Ars733618 Trs16840252 Grs231775 Grs3087243 haplotypes conferred decreased risks of GCA (P = 0.001 and P = 0.011, respectively). These results highlight that the rare CTLA4 haplotypes may affect the development of GCA in the Chinese population.

Association between cytotoxic T-lymphocyte antigen-4 +49A/G polymorphism and colorectal cancer risk: a meta-analysis

The Cytotoxic T-Lymphocyte Antigen-4 (CTLA-4) gene has been implicated in the development of colorectal cancer (CRC). However, the results are inconsistent. In this study, we performed a meta-analysis to assess the associations between the CTLA-4 +49A/G polymorphism and risk of CRC. Relevant studies were identified using PubMed, Web of Science, CNKI and WanFang databases up to November 10, 2014. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to assess the strength of the association using the fixed or random effect model. A total of 8 case-control studies, including 1180 cases and 2110 controls, were included. Overall, a significant association between the CTLA-4 +49A/G polymorphism and CRC risk was found (dominant model: OR=1.63, 95% CI: 1.09-2.43; AG vs. AA: OR=1.69, 95% CI: 1.15-2.48). In the subgroup analysis by ethnicity, we observed a significant association in Asian descent (dominant model: OR=2.42, 95% CI: 1.40-4.16; AG vs. AA: OR=2.39, 95% CI: 1.52-3.76), but not among Europeans; when stratified by source of control, no significant association was detected in both population-based and hospital-based populations. This meta-analysis demonstrated that the CTLA-4 +49A/G polymorphism significantly increases the risk of CRC, especially for Asians.

CTLA4 polymorphisms and de novo malignancy risk after renal transplantation in Chinese recipients

Genetic polymorphisms in cytotoxic T lymphocyte-associated antigen 4 (CTLA4) play an influential role in graft rejection and the long-term clinical outcome of organ transplantation. We investigated the association of five CTLA4 single-nucleotide polymorphisms (SNPs) (rs733618 C/T, rs4553808 A/G, rs5742909 C/T, rs231775 A/G, and rs3087243 G/A) with de novo malignancy in 1463 Chinese renal transplantation (RT) recipients who underwent a 192-month follow-up. Multivariate analyses revealed that recipient rs231775 genotype is significantly associated with tumorigenesis (P = 0.012). Multiplicative interaction between rs231775 AA and possible risk factors of malignancy revealed two significant results: rs231775 AA × primary diseases and rs231775 AA × number of HLA-mismatch. The frequency of haplotype TACAG was significantly higher in the tumor group (17.07%) than that in the nontumor group (1.53%). In addition, aristolochic acid nephropathy (P = 0.003) and the time of discovery of tumor (P = 0.000) also were independently associated with tumorigenesis. Our data show that the CTLA4 genotype rs231775 AA may be one of risk factors for the development of malignancy and haplotype TACAG was susceptible haplotype in Chinese kidney transplant recipients.

Association between CTLA-4 rs231775 polymorphism and risk of colorectal cancer: a meta analysis

OBJECTIVE

Many previous studies that examined the association between CTLA-4 rs231775 polymorphism and CRC risk have produced inconsistent results. In this study, a meta-analysis was performed to systematically summarize the possible association.

METHODS

We identified relevant studies using PubMed, Embase, and China National Knowledge Infrastructure literature databases. Eligible studies were selected using specific criteria. Data were extracted independently by two authors. The pooled OR with 95% CI was estimated by applying the fixed-effects model to examine the association of interest.

RESULTS

Eight studies were identified for the meta-analysis. In overall analysis, we observed an significantly increased CRC risk attributed to the AG genotype as compared to the AA genotype (OR: 1.17, 95% CI: 1.02-1.35 for AG vs AA). Stratified analysis according to ethnicity also showed a significant association in Caucasians under the AG vs AA model (OR: 1.22, 95% CI: 1.03-1.46). No significant heterogeneity or publication bias was tested in our meta-analysis.

CONCLUSION

In conclusion, the meta-analysis suggests that rs231775 in the CTLA-4 gene may be a risk factor for CRC, especially in Caucasians.

Associations of non-melanoma skin cancer and melanoma, extra-cutaneous cancers and smoking in adults: a US population-based study

BACKGROUND

Non-melanoma skin cancer (NMSC) and melanoma are common malignancies in the US and may be associated with other types of cancer.

OBJECTIVES

We sought to determine whether NMSC and melanoma are associated with extra-cutaneous cancers and identify modifiable risk factors for such an association.

METHODS

We analysed data from 447,801 adult participants in the 1997-2011 National Health Interview Surveys. Survey logistic regression models were constructed that accounted for the complex sample weights. History of NMSC, melanoma and 27 primary extra-cutaneous cancers was assessed.

RESULTS

NMSC was associated with increased odds of one (multinomial survey logistic regression, unadjusted odds ratio [95% CI]: 2.43 [2.20-2.68]) or multiple (2.94 [2.21-3.92]) extra-cutaneous malignancies. Melanoma was also associated with increased odds of one (3.25 [2.70-3.90]) or multiple (6.11 [4.34-8.61]) extra-cutaneous malignancies. Extra-cutaneous cancers were more common in younger patients (ages 18-39 and 40-49 years) and Caucasians with NMSC or melanoma (P < 0.0001). Smokers with a history of NMSC or melanoma had even higher odds of extra-cutaneous malignancy at ages 18-39 and 40-49 years compared to smokers without NMSC or melanoma (P < 0.0001). History of NMSC was associated with higher odds of malignancies of the bladder, brain, breast, colon, oesophagus, kidney, lung, lymphoma, melanoma, prostate, soft tissue, throat/pharynx, thyroid and uterus. Melanoma was associated with malignancies of the bladder, breast, colon, kidney, lung, pancreas, prostate, soft tissue, throat/pharynx, thyroid and uterus. The prevalence of extra-cutaneous cancers increased between 1997 and 2011 in all subjects (4.51% and 5.73%, P < 0.0001), with even higher rates of increase in those with history of NMSC or melanoma.

CONCLUSIONS

Patients with history of NMSC and melanoma have increased odds of developing extra-cutaneous cancers, especially those with younger age and smoking history.

Effect of cytotoxic T-lymphocyte antigen-4, TNF-alpha polymorphisms on osteosarcoma: evidences from a meta-analysis

OBJECTIVE

Previous studies have investigated the role of cytotoxic T-lymphocyte antigen-4 (CTLA-4) and tumor necrosis factor-alpha (TNF-α) in carcinogenesis of osteosarcoma, but their results were inconsistent. We aimed to clarify the associations between CTLA-4, TNF-α polymorphism and osteosarcoma risk by using meta-analysis.

METHODS

We searched relevant studies without language restriction in PubMed, EMbase, Cochrane Library, Google Scholar databases, Chinese National Knowledge Infrastructure (CNKI) and conference literature in humans published prior to March 2013. The strengths of the associations between genetic variants and osteosarcoma risk were estimated by odds ratio (OR) with 95% confidence interval (95% CI).

RESULTS

A total of seven studies with 1,198 osteosarcoma patients and 1,493 controls were selected. Four studies were eligible for CTLA-4 (1,003 osteosarcoma and 1,162 controls), and three studies for TNF-α (195 osteosarcoma and 331 controls). Pooled results showed that rs231775 polymorphism of CTLA-4 was associated with osteosarcoma risk (GG vs. AA: OR=1.63, 95% CI=1.24-2.13; GG + GA vs. AA: OR=1.56, 95% CI=1.21-2.01; AA + GA vs. GG: OR=0.83, 95% CI=0.71-0.97; G vs. A: OR=1.21, 95% CI=1.08-1.36). No significant heterogeneity was observed across the studies. No significant associations were found between rs5742909 polymorphism of CTLA-4 or rs1800629 polymorphism of TNF-α and osteosarcoma risk.

CONCLUSIONS

These results suggest that the rs231775 polymorphism of CTLA-4 may play an important role in carcinogenesis of osteosarcoma.

The association between cytotoxic T lymphocyte-associated antigen-4 and cervical cancer

Cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) gene polymorphisms have been associated with many autoimmune diseases and malignancy susceptibility, but the relationship between CTLA-4 and cervical cancer is still controversial. Hence, a meta-analysis of the published studies for the CTLA-4 gene polymorphisms and the risk of cervical cancer was performed to evaluate the association between them. Odds ratios (ORs) and 95% confidence intervals (CIs) for the codominant, dominant, and recessive genetic models were assessed. The fixed or random effect pooled measure was selected on the basis of the heterogeneity test among studies. The heterogeneity among studies was evaluated using the I (2). Eight studies with 2,835 cases and 2,560 controls were included. In seven studies for the CTLA-4 +49A/G polymorphism, a significant association was showed between the A allele and the increased risk of cervical cancer in the codominant (OR 1.16, 95% CI 1.05-1.29), dominant (OR 1.18, 95% CI 1.03-1.36), and recessive (OR 1.24, 95% CI 1.05-1.56) models. In five studies for the CTLA-4 -318C/T polymorphism, the meta-analysis showed a significant association of the C allele with the reduced risk of cervical cancer in the codominant (OR 0.79, 95% CI 0.66-0.94) and recessive (OR 0.76, 95% CI 0.63-0.93) models. This meta-analysis suggested that +49A/G and -318C/T polymorphisms of the CTLA-4 gene were significantly associated with the risk of cervical cancer. However, further studies are required to draw a solid conclusion on the relation between the CTLA-4 polymorphism and the risk of cervical cancer.

Association between the cytotoxic T-lymphocyte antigen 4 +49A/G polymorphism and bladder cancer risk

Cytotoxic T-lymphocyte antigen 4 (CTLA-4) is a potent immunoregulatory molecule that suppresses antitumor response by downregulating T cell activation. The most studied CTLA-4 +49A/G polymorphism has been associated with various cancers risks. However, little is known about the association between CTLA-4 +49A/G polymorphism and bladder cancer risk. A hospital-based case-control study was conducted in 300 patients with bladder cancer and 300 healthy controls matched with age and sex. The CTLA-4 +49A/G polymorphism was genotyped using polymerase chain reaction-restriction fragment length polymorphism. Patients with bladder cancer had a significantly lower frequency of CTLA-4 +49GG genotype [odds ratio (OR) = 0.44, 95 % confidence interval (CI) = 0.23, 0.85; P = 0.01] and G allele (OR = 0.73, 95 % CI = 0.56, 0.96; P = 0.02) than healthy controls. When stratifying by the stage, grade, and histological type of bladder cancer, we found no statistical association. This is the first study to highlight the significant association between CTLA-4 +49A/G polymorphism and bladder cancer risk. Additional studies are needed to confirm this finding.

Ctla-4 expression and polymorphisms in lung tissue of patients with diagnosed non-small-cell lung cancer

Cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) is a potent immunoregulatory molecule that downregulates T-cell activation and thus influences the antitumor immune response. CTLA-4 polymorphisms are associated with various cancers, and CTLA-4 mRNA/protein increased expression is found in several tumor types. However, most of the studies are based on peripheral blood mononuclear cells, and much less is known about the relationship between CTLA-4 expression, especially gene expression, and its polymorphic variants in cancer tissue. In our study we assessed the distribution of CTLA-4 two polymorphisms (+49A/G and −318C/T), using TaqMan probes (rs231775 and rs5742909, resp.), and CTLA-4 gene expression in real-time PCR assay in non-small-cell lung cancer (NSCLC) tissue samples. The increased CTLA-4 expression was observed in the majority of NSCLC patients, and it was significantly correlated with TT genotype (−318C/T) and with tumor size (T2 versus T3 + T4). The presence of G allele and GG genotype in cancer tissue (+49A/G) was significantly associated with the increased NSCLC risk. Additionally, we compared genotype distributions in the corresponding tumor and blood samples and found statistically significant differences. The shift from one genotype in the blood to another in the tumor may confirm the complexity of gene functionality in cancer tissue.

CTLA-4 gene polymorphism at position +49 A>G in exon 1: a risk factor for cervical cancer in Indian women

Single nucleotide polymorphisms (SNPs) in the CTLA-4 gene exert differential effects on T-cell response to viral infection. We aimed to evaluate the association of two SNPs of the CTLA-4 gene with cervical cancer in Indian women. The two polymorphic loci, one in the promoter region -318 C>T, rs5742909 (100 cervical cancer cases and 101 controls) and the other in exon 1 +49 A>G, rs231775 (104 cervical cancer cases and 162 controls) were genotyped using polymerase chain reaction-restriction fragment length polymorphism methods. Haplotype block structure was determined using Haploview 4.2. The statistical analyses were performed using a commercially available statistical software package, whereas PyPop was used to calculate the haplotypic frequencies. In this case-control study, the A/A genotype frequency (30.76% vs. 17.6%, P = 0.01) as well as the allelic frequency for A (52.8% vs. 43.5%, P = 0.04) was significantly higher in cases compared to controls. No significant association was seen in the -318 C>T polymorphism. In forward stepwise binary logistic regression analysis considering age and parity as potential confounders, significant association was demonstrated between +49 A/A and cervical cancer. Most likely, this is the first study from India to highlight the significant association between the CTLA-4 gene +49 A/A SNP and cervical cancer, thus adding to the global knowledge of the association of this SNP with cervical cancer.

Heterozygous genetic variations of FOXP3 in Xp11.23 elevate breast cancer risk in Chinese population via skewed X-chromosome inactivation

FOXP3 (forkhead box P3: also known as IPEX, XPID) is not only a hallmark of immunosuppressive regulatory T cells (Tregs), but also an X-linked breast cancer suppressor gene expressed in tumor cells. A two-stage investigation was conducted in individuals from northern, southern and eastern China. Individuals carrying a FOXP3 rs2294021CT genotype showed about 1.5-fold increased risk of breast cancer compared with TT carriers. In a related biochemical assay, the rs2294021C allele was found to significantly enhance transcription activity, leading to higher mRNA levels of FOXP3 compared with T allele. Moreover, the number of Tregs and its corresponding interleukin-10 (IL-10) secretion were elevated whereas the proliferation of antitumor T cells was decreased in the C-allele carriers. The breast cancer oncogenes Her-2/ErbB2 and Skp2 were also found to be significantly inhibited in C-allele carriers. Moreover, skewed X-chromosome inactivation (SXCI) analysis showed that rs2294021CT carriers with SXCI showed higher risk than the homozygous carriers and CT carriers without SXCI, suggesting a possible interaction between the rs2294021CT genotype and SXCI. Taken together, these findings indicate that the rs2294021CT genotype may increase an individual's susceptibility to breast cancer by breaking the balance between Treg-mediated immune tolerance and FOXP3-controlled tumor-suppressive effect.

Functional genetic variants of CTLA-4 and risk of tobacco-related oral carcinoma in high-risk North Indian population

Single nucleotide polymorphisms (SNPs) of the CTLA-4 gene have been implicated in susceptibility to different cancer in different ethnic populations. We assessed the association of five SNPs [-1722C/T, -1661A/G and -318C/T in the promoter region49A/G in exon 1 and CT60A/G in the 3'untranslated region (UTR)] with tobacco-related oral squamous cell carcinoma (OSCC) in North Indian subjects. We genotyped 130 OSCC patients and 180 normal subjects by polymerase chain reaction- restriction fragment length polymorphism (PCR-RFLP) using BbvI, MseI, NcoI and BstEII restriction endonucleases. Among these SNPs, -1722CC, -1661AG and CT60AA genotypes were more prevalent in OSCC patients as compared to controls and in the logistic regression analysis with odd ratio (OR) 2.85, 95% CI (0.69-11.68); OR 2.48, 95% CI (1.29-4.78) and OR 3.0, 95% CI (1.43-6.28) respectively, these genotypes showed strong association with OSCC risk. With higher prevalence in controls 49GG genotype and G allele (OR 0.57, 95% CI 0.40-0.81) appeared to be protective. Moreover, TACAG, TACGA and TATAG appeared as susceptible while TACGG and CACGG appeared as protective haplotypes. These results suggest significant risk modifying effects of CTLA-4 -1722C/T, -1661A/G, -318T/C, CT60 A/G and 49A/G SNPs in tobacco-related OSCC in North Indian population.

IL-21 gene polymorphism is associated with the prognosis of breast cancer in Chinese populations

Interleukin (IL)-21, which is secreted by activated CD4(+) T cells and NKT cells, has been found to be able to influence the humoral and cell-mediated immune responses and have potent antitumor activity in animal models. This study was to investigate the impact of genetic polymorphisms in IL-21 on survival of breast cancer. Four TagSNPs of IL-21 (rs12508721C>T, rs907715G>A, rs13143866G>A, rs2221903A>G) were selected and then genotyped in 891 patients with breast cancer in Eastern and Southern Chinese populations. We then examined the associations between these SNPs and overall survival. Potential function of rs12508721C>T and association between this variation and breast cancer prognosis were further studied. Overall, 121 of the patients had died over the followed-up period of 5 years. The IL-21 rs12508721T allele predicted longer five-year survival (HR = 0.347, 95 % CI = 0.187-0.644, P < 0.0001) in the discovery cohort, the independent validation cohort (HR = 0.429, 95 % CI = 0.244-0.755, P = 0.012), and combined group (HR = 0.447, 95 % CI = 0.301-0.667, P < 0.0001). Furthermore, our luciferase assay revealed that rs12508721T variant allele had a higher transcription activity and the RT-PCR and ELISA assay showed that rs12508721 variant genotypes (CT and TT) carriers have more IL-21 expression than CC carriers (P < 0.05). Our present study established a robust association between the functional polymorphism (rs12508721C>T) in IL-21 and prognosis of breast cancer, indicating that this polymorphism may be a potential biomarker for prognosis of breast cancer.

The Effects of Functional Polymorphisms in the TGFβ1 Gene on Nasopharyngeal Carcinoma Susceptibility

Objective. Transforming growth factor β1 (TGFβ1) promotes tumor growth and metastasis in the later stage of cancer development. In this study, we explored whether TGFβ1 polymorphisms were associated with increased risk of nasopharyngeal carcinoma (NPC) in a Chinese population.

Design. Case-control study.

Setting. Hospitals of the Department of Otorhinolaryngology–Head and Neck Surgery.

Subjects and Methods. Two single nucleotide polymorphisms of TGFβ1 gene promoter -509C/T (rs1800469) and 869T/C (Leu 10 Pro, rs1800470) at exon 1 were analyzed in 522 NPC patients and 712 age- and sex-matched controls in a Chinese population, using polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP) analysis. Functional relevance of the polymorphism was determined by biochemical assays.

Results. The -509T allele carriers were associated with a significantly reduced risk of NPC as compared with the noncarriers (odds ratio [OR], 0.67; 95% confidence interval [CI], 0.53-0.89 and OR, 0.50; 95% CI, 0.31-0.67, respectively). Moreover, -509C-containing TGFβ1 promoter drove an ~1.7-fold increase in reporter expression, compared with the -509T-containing counterpart in both CNE-1 and CNE-2 cell lines. The TGFβ1 -509 CC genotype carriers had a higher TGFβ1 mRNA level than the TGFβ1 -509TT genotype carriers did ( P < .01). However, no significant association was observed between the 869T/C polymorphism and risk of NPC.

Conclusion. These findings indicate that the -509C/T polymorphism in TGFβ1 may play a vital role in mediating individual susceptibility to NPC.

Functional polymorphism rs7072793 C > T affect individual susceptibility to breast cancer by modulating CD25 transcription activity

Substantial evidence has demonstrated immune defects in breast cancer patients. They have decreased numbers of peripheral blood lymphocytes, but higher numbers of functionally suppressive CD4(+) CD25(+) Treg in both peripheral blood and tumor microenvironment. Constitutive high expression of CD25 is a pivotal characteristic of natural Treg cells. This study aims at investigating if CD25 variability affects breast carcinogenesis. Two polymorphisms (rs7072793 C > T, rs3118470 C > T) in the promoter of CD25 were selected and analyzed by a multiple independent case-control study to assess the association between CD25 genotypes and breast cancer risk. Genotyping a total of 1110 patients and 1060 healthy controls in Chinese populations showed that rs7072793 CT genotype had an odd ratio of 1.49 (95% confidence interval, 1.23-1.89) for developing breast cancer compared with CC genotype, the rs7072793 TT carriers had a further increased risk of breast cancer (OR = 2.11; 95% CI = 1.66-2.87). Furthermore, our transient transfection which focused on reporter gene expression modulated by CD25 promoter demonstrated that the presence of an rs7072793 T allele led to greater transcriptional activity than the C allele. Similarly, rs13347 T carriers were shown to have larger proportion of CD4(+) CD25(+) Tregs in the PBMCs than C carriers in the flow cytometry analysis. However, no significant differences were found in genotype frequencies at rs3118470 C > T site between cases and controls. Our findings suggest that rs7072793 C > T genetic variation in CD25 genes may be genetic modifier for developing breast cancer.

CTLA-4 +49A>G polymorphism is associated with advanced non-small cell lung cancer prognosis

BACKGROUND

Cytotoxic T lymphocyte antigen 4 (CTLA-4) is a potent immunoregulatory molecule that suppresses antitumor response by downregulating T cell activation. The most studied +49A>G polymorphism of the CTLA-4 gene has been associated with several autoimmune diseases. However, little is known about the association between this functional polymorphism of CTLA-4 and cancer prognosis.

OBJECTIVE

To investigate the association between CTLA-4 +49A>G polymorphism and prognosis of advanced non-small cell lung cancer (NSCLC) patients in a Chinese population.

METHODS

The CTLA-4 +49A>G polymorphism was detected by polymerase chain reaction-restriction fragment length polymorphism in 338 advanced NSCLC patients.

RESULTS

The frequencies of CTLA-4 +49 GG, GA and AA in advanced NSCLC patients were 44.4%, 42.0% and 13.6%, respectively. No significant association was observed between CTLA-4 +49A>G polymorphism and clinicopathologic features of advanced NSCLC including gender, histopathological type, clinical stage and tumor markers. Patients with the AA genotype had a survival time of 9.8 months, significantly shorter than those with the GG genotype (12.5 months) or the GA genotype (12.0 months) (p < 0.001; log-rank test). Multivariate Cox analysis further revealed that the CTLA-4 +49AA genotype is an independent adverse prognostic indicator for NSCLC patients.

CONCLUSION

Our data suggest that the polymorphism of CTLA-4 +49A>G is a prognostic predictor for advanced NSCLC.

Cyclin D1 (CCND1) G870A gene polymorphism is an ethnicity-dependent risk factor for digestive tract cancers: a meta-analysis comprising 20,271 subjects

Published data on the association between Cyclin D1 (CCND1) G870A gene polymorphism and digestive tract cancers (DTC) are inconclusive. We carried out a meta-analysis of published case-control studies to derive a more precise estimation of the association. Relevant studies were identified from PubMed, EMBASE, and China National Knowledge Infrastructure up to February 1st, 2011. Crude odds ratios (OR) and 95% confidence intervals (CI) were used to investigate the strength of the association. Data were available from a total of 33 case-control studies with 8534 cases and 11,737 controls. The combined results based on all studies showed that there was a statistically significant link between CCND1 G870A polymorphism and DTC risk (GG vs. AA: OR=0.83, 95%CI=0.71-0.96). In the analysis of ethnic groups, we found the A allele carriers had a significantly increased DTC susceptibility among Caucasians, but not among Asians. When stratified for tumor location, the results based on all studies only showed the variant allele 870A might have a significantly increased risk of colorectal cancer (CRC), especially of rectal cancer (GG vs. AA: OR=0.71, 95%CI=0.58-0.89). When stratifying by the stage and histological differentiation of CRC, we only observed that patients had a significantly higher frequency of CCND1 870 AA than non-cancer patients among Caucasians. The A allele carriers (hetero- or homozygotes) were significantly more common in cases with a family history of CRC than in controls. There was no evidence of publication bias for CCND1 G870A polymorphism with DTC risk. In summary, this meta-analysis demonstrates that the CCND1 G870A polymorphism may be an ethnicity-dependent risk factor for DTC. And this genetic variant may increase the risk of rectal cancer, but not colon cancer.

CDH1 -160C>A gene polymorphism is an ethnicity-dependent risk factor for gastric cancer

The associations between E-cadherin (CDH1) gene polymorphisms and gastric cancer (GC) susceptibility are still controversial. Given this uncertainty, we carried out a meta-analysis of published case-control studies to derive more precise estimations of these relationships. Relevant studies were identified from PubMed and EMBASE up to March 2011. Seventeen studies with 3511 GC cases and 4826 controls were selected. Crude odds ratios (OR) and 95% confidence intervals (CI) were used to investigate the strength of the associations. No associations between CDH1 (+54T>C, -160C>A, -347G>GA, -616G>C, -2076C>T and -3159T>C) gene polymorphisms and GC risk for all genetic models were found. As for CDH1 -160C>A polymorphism, subgroup analyses by country, gender, study design, smoking status, Helicobacter pylori infection, and the Lauren classification of GC did not change the results. When stratified by ethnicity, we found the A allele carriers had a significantly increased risk of GC among Caucasians (AA vs. CA+CC: OR=1.50, 95% CI=1.03-2.19, P=0.03), but not among Asians (AA vs. CA+CC: OR=0.87, 95% CI=0.56-1.37, P=0.56). No publication bias was found in the present study. This meta-analysis suggests that CDH1 -160C>A gene polymorphism may contribute to increased risk of GC among Caucasians.

Meta-analysis of the association between VEGF-634 G>C and risk of malignancy based on 23 case-control studies

PURPOSE

The association between polymorphism of vascular endothelial growth factor (VEGF)-634 G>C and malignancy risk has been widely studied, and no conclusive result was available up to now.

METHODS

Twenty-three case-control studies with 21,917 individuals were included in this meta-analysis through searching the databases of Medline, Embase, and CNKI (up to October 1st, 2010). The odds ratio (OR) and 95% confidence interval (95%CI) were used to investigate the strength of the association.

RESULTS

Overall, the pooled analysis showed that there was no association between VEGF-634 G>C and risk of malignancy, and the ORs (95%CIs) were 0.98 (0.85-1.12) for GG versus CC, 1.03 (0.90-1.17) for GC versus CC, 1.00 (0.89-1.13) for G carrier versus CC, and 1.08 (0.94-1.23) for C carrier versus GG. Subgroup analyses according to ethnicity, source of control, type of cancer, and sample size were also performed, and results indicated that VEGF-634 G>C was not associated with risk of malignancy for neither Asians [1.06 (0.81-1.38) for GG vs. CC and 1.08 (0.84-1.39) for GC vs. CC] nor Caucasians [0.93 (0.83-1.05) for GG vs. CC and 0.98 (0.87-1.10) for GC vs. CC]. It was also not associated with risk of breast cancer [0.95 (0.81-1.12) for GG vs. CC], gastric cancer [0.93 (0.47-1.84) for GG vs. CC], and colorectal cancer [1.17 (0.93-1.47) for GG vs. CC].

CONCLUSIONS

This meta-analysis suggests that VEGF-634 G>C may be not associated with risk of malignancy. More studies with larger sample size were needed to provide more precise evidence.