CTLA-4 gene polymorphism +49 A/G contributes to genetic susceptibility to two infection-related cancers—hepatocellular carcinoma and cervical cancer

Harnessing immunotherapy for hepatocellular carcinoma: Principles and emerging promises

HCC is considered as one of the leadin causes of death worldwide, with the ability of resistance towards therapeutics. Immunotherapy, particularly ICIs, have provided siginficant insights towards harnessing the immune system. The present review introduces the concepts and possibilities of immunotherapy for HCC treatment, emphasizing its underlying mechanisms and capacity to enhance patient results, focusing on both pre-clinical and clinical insights. The functions of TME and immune evasion mechanisms typical of HCC would be evaluated along with how contemporary immunotherapeutic approaches are designed to address these challenges. Furthermore, the clinical application of immunotherapy in HCC is discussed, emphasizing recent trial findings demonstrating the effectiveness and safety of drugs. In addition, the problems caused by immune evasion and resistance would be discussed to increase potential of immunotherapy along with combination therapy.

A Prognostic Riskscore Model Related to Helicobacter pylori Infection in Stomach Adenocarcinoma

Background: Helicobacter pylori (HP) is associated with the development of various stomach diseases, one of the major risk factors for stomach adenocarcinoma (STAD). Methods: The HP infection score between tumor and normal groups was compared by single-sample gene set enrichment analysis (ssGSEA). The key modules related to HP infection were identified by weighted gene coexpression network analysis (WGCNA), and functional enrichment analysis was conducted on these module genes. Further, the limma package was used to screen the differentially expressed genes (DEGs) between HP-positive and HP-negative STAD. The prognostic genes were obtained to construct the riskscore model, and the performance of the model was validated. The correlation between riskscore and tumor immune microenvironment (TIME) was analyzed by Spearman's method. The single-cell atlas of HP-positive STAD was delineated. The mRNA expression levels of the prognostic genes were verified using STAD cells, and the migration and invasion capacities of STAD cells were evaluated by using the wound healing assay and transwell assay. Results: The HP infection score in the tumor group was significantly higher than that in the normal group. The purple and royal blue modules showed higher correlation with HP infection in STAD, and these module genes were enriched in the immune-related pathway. Further, five prognostic genes (CTLA4, CPVL, EMB, CXCR4, and FAM241A) were screened from the HP infection-related DEGs, which were utilized for establishing the riskscore model, with good robustness. Riskscore exhibited strong correlation with TIME in STAD. Single-cell atlas of HP-positive STAD revealed that CXCR4 is highly expressed in Epithelial Cell 1, Epithelial Cell 2, and parietal cells of the tumor group. CPVL, EMB, CTLA4, FAM241A, and CXCR4 showed high expression in STAD cells, and the silencing of CPVL could suppress the migration and invasion of STAD cells. Conclusion: This study established a riskscore model based on HP infection-related genes, which could provide reference for prognostic prediction and treatment targets of STAD.

Blockade of PD-1 and CTLA-4: A potent immunotherapeutic approach for hepatocellular carcinoma

Immune checkpoints (ICPs) can promote tumor growth and prevent immunity-induced cancer cell apoptosis. Fortunately, targeting ICPs, such as programmed cell death 1 (PD-1) or cytotoxic T lymphocyte associated protein 4 (CTLA-4), has achieved great success in the past few years and has gradually become an effective treatment for cancers, including hepatocellular carcinoma (HCC). However, many patients do not respond to ICP therapy due to acquired resistance and recurrence. Therefore, clarifying the specific mechanisms of ICP in the development of HCC is very important for enhancing the efficacy of anti-PD-1 and anti-CTLA-4 therapy. In particular, antigen presentation and interferon-γ (IFN-γ) signaling were reported to be involved in the development of resistance. In this review, we have explained the role and regulatory mechanisms of ICP therapy in HCC pathology. Moreover, we have also elaborated on combinations of ICP inhibitors and other treatments to enhance the antitumor effect. Collectively, recent advances in the pharmacological targeting of ICPs provide insights for the development of a novel alternative treatment for HCC.

Impact of the cytotoxic T-lymphocyte associated antigen-4 rs231775 A/G polymorphism on cancer risk

Background

Cytotoxic T-lymphocyte associated antigen-4 (CTLA-4) is an immunosuppressive checkpoint that is involved in the development and metastasis of cancers. Several studies revealed that CTLA-4 rs231775A/G polymorphism may be associated with the risk of cancer in some populations, but the conclusions of these studies are not consistent.

Methods

We conducted a pooled analysis with eligible studies to explore the association between the CTLA-4 rs231775 variant and cancer risk. Additionally, we used in silico tools to evaluated the expression of CTLA-4 on urinary system cancer. Moreover, we adopted the enzyme-linked immunosorbent assay (ELISA), and Gene Set Enrichment Analysis (GSEA) to investigate the effects of CTLA-4 on bladder cancer (BLCA).

Results

In total, 92 case-control studies involving 29,987 patients with cancer and 36,484 healthy individuals (controls) were included in the pooled analysis. In the stratified analysis based on cancer type, the rs231775 A/G polymorphism was associated with increased bladder cancer risk in the heterozygote contrast model (OR = 1.23, 95% CI = 1.01-1.51, P = 0.040). The race-stratified analysis revealed that East Asians with the GG genotype had a 12% lower risk of developing cancer than those with the GA + AA genotype (95% CI = 0.81-0.95, P = 0.001). The in silico analysis showed that CTLA-4 expression was augmented in patients with BLCA. The ELISA results revealed that CTLA-4 expression was reduced in patients with BLCA carrying the AA genotype. Several signaling pathways, including cytokine-cytokine receptor interactions and T-cell receptor signaling, were associated with CTLA-4 expression.

Conclusion

The CTLA-4 rs231775 A/G polymorphism is associated with cancer risk in East Asian population. This polymorphism is especially associated with BLCA.

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.

Current Status of Human Papillomavirus Infection and Cervical Cancer in the Philippines

Cervical cancer is estimated to cause 341,831 deaths each year, with 9 of 10 deaths occurring in developing countries. Over the past decade, there has been a significant increase in cervical cancer incidence among women in the Philippines. Persistent infection with high-risk human papillomavirus (HPV) is the well-established necessary cause of cervical cancer. Based on limited studies conducted in the Philippines, the prevalence of infection with any HPV genotype was 93.8% for cervical squamous cell carcinoma and 90.9% for cervical adenocarcinomas. HPV types 16 and 18 were the most common HPV genotypes among Filipino patients with cervical cancer. On the other hand, the incidence of HPV infection among Filipino women with normal cervices was 9.2%. The World Health Organization has launched a global agenda of eliminating HPV infection by 2030. One of its key milestones is to vaccinate 90% of girls with the HPV vaccine by 15 years. However, the HPV vaccination rate among Filipino women remains to be unsatisfactory. HPV vaccination has only been included in the Philippine Department of Health's community-based National Immunization Program in 2015. Despite these efforts, the Philippines currently ranks last on HPV program coverage among low-middle income countries, with coverage of only 23% of the target female population for the first dose and 5% for the final dose. The principal reason for the non-acceptance of HPV vaccines was the perceived high cost of vaccination. The low utilization of available cervical cancer screening tests such as Pap smear and visual inspection with acetic acid hampered the Philippines' control and prevention of HPV infection and cervical cancer. Among those diagnosed with cervical cancer in the Philippines, only an estimated 50% to 60% receive some form of treatment. To this end, we summarize the burden of HPV infection and cervical cancer on Filipinos and the risk factors associated with the disease. We present the current screening, diagnostics, treatment, and prevention of HPV-related diseases in the Philippines. Lastly, we also propose solutions on how each building block in health systems can be improved to eliminate HPV infection and reduce the burden of cervical cancer in the Philippines.

Association of CTLA-4 and IL-4 polymorphisms in viral induced liver cancer

Background

Hepatocellular carcinoma (HCC) is one of the most prevalent types of cancer and is responsible for close to one million annual deaths globally. In Pakistan, HCC accounts for 10.7% of cancer incidence. Prior studies indicated an association between interleukin 4 (IL-4) and cytotoxic T lymphocyte protein 4 (CTLA-4) gene polymorphisms in many types of cancers, including HCC that are either hepatitis B virus (HBV)- or hepatitis C Virus (HCV)-induced. The association of IL-4 and CTLA-4 genetic polymorphisms with HCV-induced HCC is not yet determined in the Pakistani population. Therefore, this research is designed to investigate the implication of IL-4 and CTLA-4 gene polymorphisms by determining the association of IL-4 -590 C/T (rs2243250) and CTLA-4 + 49 A/G (rs231775) with HCC in Pakistan.

Methods

Different bioinformatics tools were employed to determine the pathogenicity of these polymorphisms. Samples were collected from HCV-induced HCC patients, followed by DNA extraction and ARMS-PCR analysis.

Results

The SNP analysis results indicated a positive association of IL-4 -590C/T and CTLA-4 + 49A/G gene polymorphisms with HCV-induced HCC in Pakistan. The CTLA-4 polymorphism might enhance therapeutic efficiency of HCC chemotherapy medicines. The IL-4 polymorphism might introduce new transcription factor binding site in IL-4 promoter region.

Conclusion

This study delineated risk factor alleles in CTLA-4 and IL-4 genes associated with HCV-mediated HCC among Pakistani patients that may have application to serve as genetic markers for pre- and early diagnosis and prognosis of HCC in HCV patients.

Comprehensive Analysis of 29,464 Cancer Cases and 35,858 Controls to Investigate the Effect of the Cytotoxic T-Lymphocyte Antigen 4 Gene rs231775 A/G Polymorphism on Cancer Risk

In our previous studies, we found that the rs231775 polymorphism of cytotoxic T-lymphocyte antigen 4 (CTLA-4) is associated with risks of different cancer types; however, the association remains controversial and ambiguous, so we conducted an in-depth meta-analysis to verify the association. A complete search of the PubMed, Google Scholar, Embase, Chinese databases, and Web of Science was conducted without regard to language limitations, covering all publications since November 20, 2021. The search criteria for cancer susceptibility associated with the polymorphism in the CTLA-4 gene rs231775 resulted in 87 case-control studies with 29,464 cases and 35,858 controls. The association strength was analyzed using odds ratios and 95% confidence intervals. Overall, we found that the CTLA-4 rs231775 polymorphism may reduce cancer risk. A stratified cancer type analysis showed that CTLA-4 rs231775 polymorphism was a risk factor for colorectal cancer and thyroid cancer; on the other hand, it was a protective factor for breast cancer, liver cancer, cervical cancer, bone cancer, head and neck, and pancreatic cancer. We also classified cancer into five systems and observed an increased association with digestive tract cancer, decreased associations with orthopedic tumors, tumors of the urinary system, and gynecological tumors. In the subgroup based on race, decreased relationships were observed in both Asians and Caucasians. The same decreased association was also shown in the analysis of the source of control analysis. Our present study indicates that the CTLA-4 rs231775 polymorphism contributes to cancer development and aggression.

CTLA-4 polymorphism contributes to the genetic susceptibility of epithelial ovarian cancer

AIM

Cytotoxic T-lymphocyte antigen-4 (CTLA-4), an inhibitory molecule on T-cells, plays a key role in tumorigenesis and progression. In the present study, we investigated the effects of three polymorphisms in the CTLA-4 gene on the risk of epithelial ovarian cancer and the clinical outcomes of patients.

METHODS

A case-control study was performed in 527 epithelial ovarian cancer patients and 532 controls. Genotypes of three polymorphisms were determined by polymerase chain reaction/ligase detection reaction. A survival analysis was performed in 346 patients who were followed up for more than 3 years and 208 patients who were followed up for more than 5 years.

RESULTS

There were significant differences in the genotype and allele distribution frequencies of the rs5742909 C/T polymorphism in CTLA-4 between patients and controls (p = 0.009 and p = 0.04, respectively). Compared with the CC genotype, the CT + TT genotype may significantly decrease the risk of developing epithelial ovarian cancer (OR = 0.69, 95% CI = 0.52-0.91). However, no significant association between the rs231775 G/A and rs3087243 G/A polymorphisms and epithelial ovarian cancer risk was observed. The survival analysis showed that three polymorphisms may not be related to the clinical outcomes of patients.

CONCLUSION

Our results suggested that the rs5742909 C/T polymorphism of CTLA-4 may decrease the genetic susceptibility to epithelial ovarian cancer among northern Chinese women.

Genomic Risk Factors for Cervical Cancer

Cervical cancer is the fourth common cancer amongst women worldwide. Infection by high-risk human papilloma virus is necessary in most cases, but not sufficient to develop invasive cervical cancer. Despite a predicted genetic heritability in the range of other gynaecological cancers, only few genomic susceptibility loci have been identified thus far. Various case-control association studies have found corroborative evidence for several independent risk variants at the 6p21.3 locus (HLA), while many reports of associations with variants outside the HLA region remain to be validated in other cohorts. Here, we review cervical cancer susceptibility variants arising from recent genome-wide association studies and meta-analysis in large cohorts and propose 2q14 (PAX8), 17q12 (GSDMB), and 5p15.33 (CLPTM1L) as consistently replicated non-HLA cervical cancer susceptibility loci. We further discuss the available evidence for these loci, knowledge gaps, future perspectives, and the potential impact of these findings on precision medicine strategies to combat cervical cancer.

Investigation of the relationship between CTLA4 and the tumor suppressor RASSF1A and the possible mediating role of STAT4 in a cohort of Egyptian patients infected with hepatitis C virus with and without hepatocellular carcinoma

The Ras association domain family 1 isoform A (RASSF1A), cytotoxic T lymphocyte antigen 4 (CTLA-4), and signal transducer and activator of transcription 4 (STAT4) genes play a role in regulating the cell cycle, apoptosis, and the autoimmune response against cancer. We investigated the genotype frequency and the possible association of the rs2073498 (RASSF1A), rs5742909 (CTLA-4) and rs7574865 (STAT4) genetic variants with hepatitis C virus (HCV)-G4-mediated hepatocellular carcinoma (HCC) progression in Egyptian patients. Fifty patients with HCV infection, 50 patients with HCV-mediated HCC, and 50 age- and sex-matched healthy controls were recruited. The investigated variants were genotyped based on polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP). The Ser133 mutant G4 variant of the rs2073498 SNP in RASSF1A exhibited a positive correlation with HCC incidence risk (OR = 0.571, 95% CI = 0.175-1.865, P < 0.001). The rs7574865 variant in STAT4 (G/T) occurred frequently in both HCV groups, with a significant incidence risk (OR = 1.583, 95% CI = 1.123-2.232, P = 0.005). The rs5742909 change in CTLA4 (C/T) did not show a significant difference between HCV-mediated HCC cases and the control group (OR = 4.5, 95% CI = 1.326-15.277, P > 0.001). Activation of the immune checkpoint gene CTLA4 or polymorphism in the encoded CTLA4 protein causes phosphorylation of kinases needed for RAS gene activation. This in turn downregulates the tumor suppressor RASSF1, inhibiting apoptosis and leading to HCC development, indicating a negative impact of CTLA4 gene polymorphism on HCV-mediated HCC cases. A major determinant of disease progression could be immune system genetic variants, together with the presence of costimulatory factors. The rs2073498 and rs7574865 variations in the RASSF1A and STAT4 genes, respectively, could be genetic susceptibility factors for Egyptian patients with HCV-mediated HCC.

Immune Checkpoint Molecules-Inherited Variations as Markers for Cancer Risk

In recent years, immunotherapy has been revolutionized by a new approach that works by blocking receptors called immune checkpoints (IC). These molecules play a key role in maintaining immune homeostasis, mainly by suppressing the immune response and by preventing its overactivation. Since inhibition of the immune response by IC can be used by cancer to avoid recognition and destruction by immune system, blocking them enhances the anti-tumor response. This therapeutic approach has brought spectacular clinical effects. The ICs present heterogeneous expression patterns on immune cells, which may affect the effectiveness of immunotherapy. The inherited genetic variants in regulatory regions of ICs genes can be considered as potential factors responsible for observed inter-individual differences in ICs expression levels on immune cells. Additionally, polymorphism located in exons may introduce changes to ICs amino acid sequences with potential impact on functional properties of these molecules. Since genetic variants may affect both expression and structure of ICs, they are considered as risk factors of cancer development. Inherited genetic markers such as SNPs may also be useful in stratification patients into groups which will benefit from particular immunotherapy. In this review, we have comprehensively summarized the current understanding of the relationship between inherited variations of CTLA-4, PDCD1, PD-L1, BTLA, TIM-3, and LAG-3 genes in order to select SNPs which can be used as predictive biomarkers in personalized evaluation of cancer risk development and outcomes as well as possible response to immunotherapy.

Association of cytotoxic T lymphocyte-associated protein 4 gene -1772T/C polymorphism with gastric cancer risk: A prisma-compliant meta-analysis

BACKGROUND

We performed a meta-analysis to more precisely evaluate the association between the cytotoxic T lymphocyte-associated protein 4 (CTLA-4) -1772T/C polymorphism and overall gastric cancer (GC) risk and the influence of ethnicity and the source of controls on that association.

METHODS

A systematic literature search was performed in PubMed, EMBASE, the Cochrane Library, Web of Science (WOS) Database, Chinese National Knowledge Infrastructure (CNKI), China biomedical literature database (CBM), Wanfang database, and VIP. Two investigators independently reviewed the articles, and disagreements were resolved by discussion and consensus. The odds ratio (OR) with 95% confidence intervals (CIs) was used to assess the strength of the association between the CTLA-4 -1722T/C polymorphism and GC risk, based on the genotype frequencies in cases and controls. The meta-analyses were performed with Stata 12.0, using two-sided P values. Trial sequential analysis (TSA) was calculated by TSA Software.

RESULTS

Overall, we identified 5 studies including 1039 GC cases and 2136 controls that evaluated the association of the CTLA-4 -1722T/C polymorphism and GC risk. Overall, there was no significant association between the CTLA-4-1722T/C polymorphism and the risk of GC. In the subgroup analysis based on ethnicity, the results showed that the relationship between the CTLA-4 -1722T/C polymorphism and GC susceptibility was strongest in the Chinese population rather than in the Iranian population (TC vs CC: OR = 1.405, 95% CI: 1.100-1.796, P = .007; TC+TT vs CC: OR = 1.329, 95% CI: 1.052-1.680, P = .017). Then, there was a significant association between the CTLA-4 -1722T/C polymorphism and the risk of GC in studies with HB controls. However, the above correlation can only be reflected in specific populations and gene models. Therefore, we believe that the evidence of this correlation is insufficient.

CONCLUSION

Our meta-analysis showed that the CTLA-4 -1722T/C polymorphism may be associated with the susceptibility to GC. However, the slight correlation can only be reflected in specific populations and gene models. Therefore, we believe that this association is negligible. The large and well-designed case-control studies are needed to validate our findings.

Impacts of CD152 polymorphisms on cervical cancer susceptibility

AIM

The objective of this study was to discuss the effect of CD152 polymorphisms rs231775, rs3087243 and rs5742909 on the susceptibility to cervical cancer.

METHODS

The databases of PubMed, EMBASE, Cochrane Library, ISI Web of Science, Google Scholar Web, CNKI and Wanfang were searched for eligible studies. Chi-square-based Q test examined heterogeneity between included studies, and when P_{heterogeneity} was less than 0.05, random-effect model was used to calculate odds ratios (ORs) with their 95 % confidence intervals (95 % CIs); or else, fixed-effect model was selected. Sensitivity analysis was implemented to determine the stability of final results through removing enrolled studies one at a time and then re-obtaining overall estimates. Publication bias among included studies was checked employing Begg's funnel plot and Egger's test.

RESULTS

CD152 polymorphism rs231775 decreased cervical cancer risk in total analysis under the genetic models of GG vs. AA, GG vs. AA + AG and G vs. A (OR = 0.73, 95 % CI = 0.59-0.91; OR = 0.78, 95 % CI = 0.65-0.94; OR = 0.92, 95 % CI = 0.87-0.98), and so did the polymorphism rs3087243 in total analysis under the comparisons of AA vs. GG, AA + GA vs. GG, AA vs. GG + GA, A vs. G and GA vs. GG (OR = 0.51, 95 % CI = 0.42-0.60; OR = 0.71, 95 % CI = 0.62-0.82; OR = 0.57, 95 % CI = 0.50-0.66; OR = 0.70, 95 % CI = 0.64-0.77; OR = 0.83, 95 % CI = 0.72-0.97). Besides, the polymorphism rs5742909 elevated the disease onset in total analysis under the contrasts of TT vs. CC, TT + CT vs. CC, TT vs. CC + CT, T vs. C and CT vs. CC (OR = 2.66, 95 % CI = 1.75-4.04; OR = 1.54, 95 % CI = 1.24-1.91; OR = 2.13, 95 % CI = 1.12-4.03; OR = 1.44, 95 % CI = 1.17-1.78; OR = 1.49, 95 % CI = 1.22-1.83).

CONCLUSION

CD152 polymorphisms rs231775 and rs3087243 significantly decrease the risk of cervical cancer, while rs5742909 may increase the disease risk.

Genetic variations in the CXCR5 gene decrease the risk of clinical relapse after discontinuation of nucleos(t)ide analogue therapy in patients with chronic hepatitis B

Discontinuation of nucleos(t)ide analogue (NA) therapy in patients with chronic hepatitis B (CHB) remains a global but controversial problem. Clinical outcomes of NA cessation depend on the interplay between viral factors and host immunity. Recent studies have shown that genetic polymorphisms might influence the immune response in chronic HBV infection. A total of 33 single-nucleotide polymorphisms (SNPs) from 16 genes (BCL6, CD40, CD40L, CTLA-4, CXCL13, CXCR5, ICOS, IL-21, HLA-C, NTCP, UBE2L3, STAT4, IFN-λ3, CYP27B1, INST10, and IPS1) were selected and analyzed in 106 CHB patients enrolled in an off-treatment cohort. Significantly unbalanced distributions between patients who experienced clinical relapse and those who did not were found regarding two SNPs, rs676925 in CXCR5 and rs733618 in CTLA-4. Furthermore, the genotype 'GC' of rs676925 were associated with decreased risk of clinical relapse, implicating that rs676925 may serve as a protective factor for HBV control and facilitate a virus-specific immune response. We also compared the expression of CXCR5 in lymphocytes and its ligand CXCL13 in plasma between different genotypes of rs676925. However, no significant differences were observed. In conclusion, this study suggested that the rs676925 'GC' genotype of the CXCR5 gene were associated with decreased risk of clinical relapse after discontinuation of long-term NA therapy in CHB patients.

Stimulatory and Inhibitory Co-signals in Autoimmunity

Co-receptors cooperatively regulate the function of immune cells to optimize anti-infectious immunity while limiting autoimmunity by providing stimulatory and inhibitory co-signals. Among various co-receptors, those in the CD28/CTLA-4 family play fundamental roles in the regulation of lymphocytes by modulating the strength, quality, and/or duration of the antigen receptor signal. The development of the lethal lymphoproliferative disorder and various tissue-specific autoimmune diseases in mice deficient for CTLA-4 and PD-1, respectively, clearly demonstrates their pivotal roles in the development and the maintenance of immune tolerance. The recent success of immunotherapies targeting CTLA-4 and PD-1 in the treatment of various cancers highlights their critical roles in the regulation of cancer immunity in human. In addition, the development of multifarious autoimmune diseases as immune-related adverse events of anti-CTLA-4 and anti-PD-1/PD-L1 therapies and the successful clinical application of the CD28 blocking therapy using CTLA-4-Ig to the treatment of arthritis assure their crucial roles in the regulation of autoimmunity in human. Accumulating evidences in mice and humans indicate that genetic and environmental factors strikingly modify effects of the targeted inhibition and potentiation of co-signals. In this review, we summarize our current understanding of the roles of CD28, CTLA-4, and PD-1 in autoimmunity. Deeper understandings of the context-dependent and context-independent functions of co-signals are essential for the appropriate usage and the future development of innovative immunomodulatory therapies for a diverse array of diseases.

Association of CTLA-4, TNF alpha and IL 10 polymorphisms with susceptibility to hepatocellular carcinoma

Our aim was to evaluate the association of genetic polymorphisms of immunoregulatory molecules with susceptibility to hepatocellular carcinoma (HCC). The polymorphisms in CTLA-4 (-318 T/C, CT60 G/A), TNF (-238 G/A, -308 G/A) and IL10 (-592 C/A, -819 C/T) were genotyped by PCR and DNA sequencing. The functional relevance of the polymorphisms was examined by ELISAs, in vitro lymphocyte proliferation assay and cytotoxic assay. The CTLA-4 -318 TC/TT, CTLA-4 CT60 GG, IL10 -592 CA and -819 CT/TT variants, CTLA-4 -318 T and IL 10 -819 T alleles were positively associated with HCC risk (P < .05). While TNF -238 AA variant, TNF -238 A allele were associated with decreased risk of HCC (P < .05). Furthermore, combinations of CTLA-4 -318 TC/TT and TNF -238 GG/GA; CTLA-4 -318 TC/TT and IL 10 -819 CC; CTLA-4 -318 CC and IL 10 -819 CT/TT in patients with HCC were statistically significant (P < .05). Peripheral blood mononuclear cells (PBMCs) carrying -318 TC/TT genotypes exhibited significantly lower proliferation rates, decreased IL-2, IL-4 levels, fewer cytolytic activities and elevated TGF-β levels. For IL 10 -819 C/T, the CC genotype was significantly associated with higher proliferation rate, decreased TGF-β, IL-10 levels and higher cytolytic activities (P < .05). For TNF -238 G/A, the AA genotype only had association with serum IL-2, IL-4 (P < .05). In addition, we also found that CTLA-4 -318 T/C, IL-10 -819 T/C variants, combinations of CTLA-4 -318 CC with IL 10 -819 CT or TT, CTLA-4 -318 TC or TT with IL 10 -819 CT or TT were associated with the severity of HCC. These findings suggest that CTLA-4 -318 TC/TT and IL 10 -819 CT/TT could promote the pathogenesis of HCC, which might be related with down-regulation of Th1/Th2-type cytokines and/or up-regulation of Th3-type cytokines.

Association of CTLA-4 tagging polymorphisms and haplotypes with hepatocellular carcinoma risk: A case-control study

It has been proposed that cytotoxic T-lymphocyte antigen 4 (CTLA-4) may attenuate the T-cell activation threshold, thereby decreasing the antitumor response and conferring susceptibility to hepatocellular carcinoma (HCC).In the present study, we selected CTLA-4 tagging single nucleotide polymorphisms (SNPs) and explored the relationship between these polymorphisms and susceptibility to HCC. A hospital-based case-control study, comprising 584 cases with HCC and 923 controls, was performed in an eastern Chinese Han population. CTLA-4 SNPs were genotyped using a custom-by-design 48-Plex SNPscan Kit.We found that the CTLA-4 rs3087243 G>A polymorphism might be associated with increased risk of HCC (GA vs GG: adjusted odds ratio [OR], 1.38; 95% confidence interval [CI], 1.04-1.85; P = .028 and AA/GA vs GG: adjusted OR, 1.43; 95% CI, 1.08-1.89; P = .012). After using Bonferroni correction, this association remained (P = .012 for the AA/GA vs GG genetic model). In addition, the power value was 0.904 in the AA/GA versus GG genetic model. Haplotype analysis showed that CTLA4 Crs16840252Ars231775Ars3087243Trs733618, Crs16840252Grs231775Ars3087243Trs733618, and other haplotypes might increase the risk of HCC risk (P = .018, <.001, and .017, respectively). However, we found that CTLA4 Trs16840252A rs231775Grs3087243Trs733618 decreased the risk of HCC (P = .020).Our results suggest that the CTLA-4 rs3087243 G>A polymorphism increases susceptibility to HCC in an eastern Chinese Han population. CTLA-4 haplotypes may influence the development of HCC. In the future, a population-based fine-mapping study with functional assessment should be performed to further determine these potential correlations.

Polymorphisms in cytotoxic T-lymphocyte associated antigen 4 gene does not affect scytotoxic T-lymphocyte associated antigen 4 levels in human papillomavirus-infected women with or without cervical cancer

Background

Cervical cancer (CaCx) is the second most common cancer in Indian women. Cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) + 49 AA polymorphism is known to be associated with CaCx. Current attempt is to use immunotherapy for the treatment of metastatic melanoma and metastatic castration-resistant prostate cancer, i.e., blocking of CTLA-4 using a fully human monoclonal CTLA-4 antibody to disrupt its inhibitory signal. This allows the CTLs to destroy the cancer cells. There is no information available on the soluble level of CTLA-4 on which the immunotherapy is targeted. This is specifically in Indian population including cases with CaCx.

Objective

The aim of this study is to evaluate the levels of soluble CTLA-4 (sCTLA-4) in human papillomavirus (HPV)-infected women with or without CaCx and their association with the polymorphism at CTLA-4 + 49 A/G and CTLA-4 -318 C/T genotypes.

Materials and Methods

This is an exploratory case-control study involving two groups of HPV-infected women, the cases were with invasive CaCx and the control group was women with the healthy cervix. sCTLA-4 levels were measured using ELISA in 92 CaCx cases and 57 HPV-positive women with the healthy cervix.

Results

Both cases and controls have similar sCTLA-4 levels. Comparison of CTLA-4 + 49A/G and -318 C/T genotypes with sCTLA-4 levels among cases and control also did not show any statistically significant difference.

Conclusion

The present study suggests sCTLA-4 levels are not affected by a polymorphism at + 49 A>G CTLA-4. Hence, levels of CTLA-4 are similar in both CaCx cases and control group.

Genetic susceptibility in cervical cancer: From bench to bedside

Cervical cancer (CC) is the third most common malignancy in women globally, and persistent infection with the oncogenic human papillomaviruses (HPV) is recognized as the major risk factor. The pathogenesis of CC relies on the interplay between the tumorigenic properties of the HPV and host factors. Host-related genetic factors, including the presence of susceptibility loci for cervix tumor is substantial importance. Preclinical and genome-wide association studies (GWAS) have reported the associations of genetic variations in several susceptibility loci for the development of cervical cancer. However, many of these reports are inconsistent. In this review, we discuss the findings to date of candidate gene association studies, and GWAS in cervical cancer. The associations between these genetic variations with response to chemotherapy are also discussed.

Check point inhibitors as therapies for infectious diseases

The recent successes of immune check point targeting therapies in treating cancer patients has driven a resurgence of interest in targeting these pathways in chronically infected patients. While still in early stages, basic and clinical data suggest that blockade of CTLA-4 and PD-1 can be beneficial in the treatment of chronic HIV, HBV, and HCV infection, as well as other chronic maladies. Furthermore, novel inhibitory receptors such as Tim-3, LAG-3, and TIGIT are the potential next wave of check points that can be manipulated for the treatment of chronic infection. Blockade of these pathways influences more than simply T cell responses, and may provide new therapeutic options for chronically infected patients.

Current evidence on the cytotoxic T-lymphocyte antigen 4 + 49G > A polymorphism and digestive system cancer risks: a meta-analysis involving 11,923 subjects

Cytotoxic T-lymphocyte antigen (CTLA-4) plays an important role in downregulating T cell activation and proliferation. The CTLA-4 + 49G > A polymorphism is one of the most commonly studied polymorphisms in this gene due to its association with many cancer types, but the association between CTLA-4 + 49G > A polymorphism and digestive system cancer risks remain inconclusive. An updated meta-analysis based on 17 independent case-control studies consisting of 5176 cancer patients and 6747 controls was performed to address this association. Overall, there was no statistically increased risk of digestive system cancers in every genetic comparison. In subgroup analysis, this polymorphism was significantly linked to higher risks for pancreatic cancer (GG vs. AA, OR = 1.976, 95% CI = 1.496-2.611; GA vs. AA, OR = 1.433, 95% CI = 1.093-1.879; GG/GA vs. AA, OR = 1.668, 95% CI = 1.286-2.164; GG vs. GA/AA, OR = 1.502, 95% CI = 1.098-2.054; G vs. A, OR = 1.394, 95% CI = 1.098-1.770). We also observed increased susceptibility of hepatocellular cell carcinoma in homozygote comparison (OR = 1.433, 95% CI = 1.100-1.866) and dominant model (OR = 1.360, 95% CI = 1.059-1.746). According to the source of controls, significant effects were only observed in hospital-based studies (GA/AA vs. GG, OR = 1.257, 95% CI = 1.129-1.399). In the stratified analysis by ethnicity, no significantly increased risks were found in either Asian or Caucasian. Our findings suggest that the CTLA-4 + 49G > A polymorphism may be associated with the risk of pancreatic cancer and hepatocellular cell carcinoma.

Puzzling role of genetic risk factors in human longevity: "risk alleles" as pro-longevity variants

Complex diseases are major contributors to human mortality in old age. Paradoxically, many genetic variants that have been associated with increased risks of such diseases are found in genomes of long-lived people, and do not seem to compromise longevity. Here we argue that trade-off-like and conditional effects of genes can play central role in this phenomenon and in determining longevity. Such effects may occur as result of: (i) antagonistic influence of gene on the development of different health disorders; (ii) change in the effect of gene on vulnerability to death with age (especially, from “bad” to “good”); (iii) gene–gene interaction; and (iv) gene–environment interaction, among other factors. A review of current knowledge provides many examples of genetic factors that may increase the risk of one disease but reduce chances of developing another serious health condition, or improve survival from it. Factors that may increase risk of a major disease but attenuate manifestation of physical senescence are also discussed. Overall, available evidence suggests that the influence of a genetic variant on longevity may be negative, neutral or positive, depending on a delicate balance of the detrimental and beneficial effects of such variant on multiple health and aging related traits. This balance may change with age, internal and external environments, and depend on genetic surrounding. We conclude that trade-off-like and conditional genetic effects are very common and may result in situations when a disease “risk allele” can also be a pro-longevity variant, depending on context. We emphasize importance of considering such effects in both aging research and disease prevention.

HCV F protein amplifies the predictions of IL-28B and CTLA-4 polymorphisms about the susceptibility and outcomes of HCV infection in Southeast China

Cytotoxic T lymphocyte associated antigen-4(CTLA-4) is an inhibitory receptor with great value in the progression of hepatitis C virus (HCV) infection related diseases. To determine the potential associations of IL-28B rs12979860 and CTLA-4 rs231775, rs3087243 and rs5742909 polymorphisms with the generation of HCV F protein, susceptibility and outcomes of HCV infection, a total of 375 healthy controls, 219 HCV spontaneous recovered patients and 600 chronic HCV patients from Southeast China were recruited and genotyped in this study. And the relative mRNA levels of CTLA-4 in T cells were detected. Logistic regression analysis showed that rs231775 A allele was associated with significantly higher rate of spontaneous viral clearance in anti-HCV F antibody negative patients (adjusted OR=0.512, P=0.008), but allele A was related to higher mRNA level of CTLA-4 with the generation of HCV F protein. And rs5742909 T allele added up to the risk of HCV infection chronicity significantly in patients with the presence of HCV F protein (adjusted OR=2.698, P=0.003). Also, the rs5742909 CC genotype, along with the presence of HCV F protein, indicated a significantly higher CTLA-4 level than that in anti-HCV F antibody negative patients. The AG+AA genotype of rs3087243 significantly increased the susceptibility to HCV infection in subjects over 56 years old (adjusted OR=1.595, P=0.011). Genotype-genotype interaction between IL-28B rs12979860 and CTLA-4 rs3087243 was found to be significantly associated with increased susceptibility to HCV infection (adjusted OR=1.509, P=0.005). Haplotype analysis in CTLA-4 also showed significant association with the generation of HCV F protein. All these results indicated the importance of IL-28B and CTLA-4 polymorphisms and their associations with HCV F protein in the risk and chronicity of HCV infection in Chinese Han population in Southeast China.

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.

Lack of association between cytotoxic T-lymphocyte antigen 4 (CTLA-4) -1722T/C (rs733618) polymorphism and cancer risk: from a case-control study to a meta-analysis

BACKGROUND

The association between cytotoxic T-lymphocyte antigen 4 (CTLA-4) gene -1722T/C polymorphism (rs733618) and cancer has been widely assessed, and a definitive conclusion remains elusive. We first performed a hospital based case-control study to measure this association of esophageal cancer with CTLA-4 -1722T/C polymorphism in Han Chinese population, and then carried out a meta-analysis to obtain a comprehensive evaluation for this issue.

METHODOLOGY/PRINCIPAL FINDINGS

This case-control study involved 629 esophageal squamous cell carcinoma (ESCC) cases and 686 age and gender well matched cancer-free controls. PCR-LDR (polymerase chain reaction-ligase detection reactions) method was used to identify genotypes. Meta-analysis was conducted by STATA (v12.0) software. This case-control study showed no significant difference in the genotype and allele distributions of CTLA-4 -1722T/C polymorphism between esophageal cancer cases and control subjects, in accord with the findings of the further meta-analysis in all genetic models. Evidence of large heterogeneity was observed among all eligible studies in the recessive model. Further subgroup analyses by ethnicity, cancer type and system, detected null associations in this meta-analysis.

CONCLUSION

This case-control study and the further meta-analysis, failed to identify the association between CTLA-4 -1722T/C polymorphism and cancer risk.

Monitoring the immune competence of cancer patients to predict outcome

A new era of cancer immunotherapy has brought not only successful cancer vaccines but also immunomodulators, such as those that target checkpoint blockade in order to induce endogenous host immune responses. However, the immune system of cancer patients can be compromised through multiple means, including immune suppression by the tumor and by prior therapies such as chemotherapy and radiation. Therefore, a comprehensive means of assessing patient immunocompetence would seem helpful for determining whether patients are ready to benefit from immunotherapy, and perhaps even which immunotherapy might be most appropriate for them. Unfortunately, there are no standardized tests for immune competence, nor is there agreement on what to measure and what will be predictive of outcome. In this review, we will discuss the technologies and assays that might be most useful for this purpose. We argue for a comprehensive approach that should maximize the chances of developing predictive biomarkers for eventual clinical use.

Spontaneous and therapeutic immune responses in hepatocellular carcinoma: implications for current and future immunotherapies

Hepatocellular carcinoma (HCC) represents a major health problem in the world, ranking fifth in incidence and third in cancer-related deaths. Due to the unique immunosuppressive microenvironment of the liver, HCC develops in an immunotolerant niche posing an important obstacle to immunotherapy. A number of studies, however, have shown immunogenic properties of HCC by demonstrating spontaneous adaptive immune responses during tumor formation and progression. Furthermore, studies examining immune responses during HCC therapy have revealed that conventional treatments such as surgical resection, locoregional therapy and systemic therapy with antibodies, small molecules or chemotherapy induce adaptive immune responses that contribute to therapeutic effects. These observations have provided a basis for clinical trials involving adoptive transfers of T cells or natural killer cells, peptide and dendritic cell vaccinations or, more recently, virotherapy and inhibition of co-inhibitory molecules. Here, spontaneous and therapeutic immune responses in HCC and their implication for current and future immunotherapies are discussed.

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 cytotoxic T lymphocyte antigen-4 +49A/G, -1722T/C, and -1661A/G polymorphisms and cancer risk: a meta-analysis

Cytotoxic T lymphocyte antigen-4 (CTLA-4), a key gene that contributes to the susceptibility and clinical course of cancer, is an important down-regulator of T cell activation and proliferation. The +49A/G polymorphism is commonly studied because of its association with cancer risks. However, other polymorphisms, such as -1722T/C and -1661A/G, have not been studied in detail. We performed a meta-analysis using 43 eligible case-control studies with a total of 19,089 patients and 21,388 controls to examine the association between CTLA-4 +49A/G, -1722T/C, and -1661A/G polymorphisms and cancer risk. We searched the PubMed and EMBASE databases for all articles published up to July 17, 2013. Individuals with the +49 A allele (AA/AG vs. GG, odds ratio (OR) = 1.21, 95% confidence interval (95% CI) = 1.16-1.27) and -1661 G allele (AG/GG vs. AA, OR = 1.52, 95% CI = 1.34-1.73) had increased cancer risk. However, no significant association between cancer risk and the -1722T/C polymorphism was found (CC/CT vs. TT, OR = 1.04, 95% CI = 0.92-1.16). In subgroup analysis for the +49A/G polymorphism, increased cancer risk remained in the subgroups of Asians (OR = 1.25, 95 % CI = 1.18-1.31), patients with breast cancer (OR = 1.28, 95% CI = 1.15-1.42), and patients with lung cancer (OR = 1.20, 95 % CI = 1.07-1.35). For the -1661A/G polymorphism, increased cancer risk remained in the subgroups of Asians (OR = 1.52, 95% CI = 1.34-1.73), patients with breast cancer (OR = 1.48, 95% CI = 1.07-2.03), and patients with oral cancer (OR = 3.16, 95% CI = 1.84-5.45). However, no significant increase in cancer risk was found in the subgroups for the -1722T/C polymorphism. In conclusion, the results suggest that +49A/G and -1661A/G polymorphisms in CTLA-4 are risk factors for cancers, whereas the -1722T/C polymorphism is not associated with an increased risk of cancer.

Influence of cytotoxic T lymphocyte-associated antigen 4 polymorphisms on the outcomes of hepatitis B virus infection

Cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) regulates T-cell activation and Th1/Th2 cytokine production and is involved in the immune response against Hepatitis B virus (HBV) infection. To detect the association of the CTLA-4 gene polymorphisms with susceptibility to HBV infection a hospital-based case-control study was conducted. A total of 1,119 unrelated individuals were recruited. The CTLA-4 variants rs5742909, rs231775 and rs3087243 were genotyped via the TaqMan method in this cohort. A comparison with a chronic active hepatitis B group revealed that the SNP rs231775 exhibited significant susceptibility to HBV progression, with the highest odds ratio (OR) reaching 1.659 and P=0.009-0.049. Although an HBV clearance group was used as a control, results of the present study demonstrated an association of rs5742909 with viral persistence [OR=1.694, 95% confidence intervals (CI)=1.124-2.553 and P=0.012]. Subsequent analyses revealed risk haplotypes (C-A-A and T-A-G, for which the highest OR reached 1.865) compared with the protective haplotype C-G-G. Therefore, SNPs in the CTLA-4 gene may be associated with HBV progression and viral persistence which is consistent with its emerging role in the T regulatory cells in the pathogenesis of disease.

Cytotoxic T‑lymphocyte-associated antigen‑4 polymorphisms and susceptibility to cervical cancer: a meta‑analysis

Cytotoxic T‑lymphocyte associated antigen‑4 (CTLA‑4) polymorphisms have been examined for associations with cervical cancer in various countries. The results, however, are inconclusive. The present study aimed to explore whether CTLA‑4 +49 A/G, ‑318 C/T and CT60 G/A polymorphisms confer susceptibility to cervical cancer. A meta‑analysis was performed with 7,794 subjects included in 15 case‑control studies that were published up to January 1, 2013. The results from the meta‑analysis indicated that there were no significant associations between the risk of cervical cancer and the three studied polymorphisms [+49 A/G: Odds ratio (OR), 0.94 and 95% confidence interval (CI), 0.82‑1.07 for GG+AG vs. AA; ‑318 C/T: OR, 1.33 and 95% CI, 0.82‑2.16 for TT+TC vs. CC; and CT60: OR, 0.98 and 95% CI, 0.72‑1.33 for AA+AG vs. GG]. Stratified analyses by ethnicity for the +49 A/G and ‑318 C/T polymorphisms suggested that Asian populations had a decreased risk of cervical cancer for the +49 A/G polymorphism (OR, 0.75 and 95% CI, 0.58‑0.97 for GG+AG vs. AA), but an increased risk for the ‑318 C/T polymorphism (OR, 2.02 and 95% CI, 1.36‑3.00 for TC vs. CC). In summary, the current meta‑analysis showed that the +49 A/G and ‑318 C/T polymorphisms in CTLA‑4 constitute risk factors for 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 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.

Genetic susceptibility of cervical cancer

Epidemiological and laboratory-based studies have identified infection with one of 15 high-risk human papillomavirus (HPV) types as a necessary but not sufficient cause of cervical cancer. The prevalence of genital HPV infections is high in young women, but most of the infections regress without interventions. Host genetic variations in genes involved in immune response pathways may be related to HPV clearance, and HPV E6/E7 oncoproteins interacting or downstream genes, both coding and non-coding, may contribute to the outcome of high risk HPV infection and cervical cancer. Of specific interest for this review has been the selection of genetic variants in genes involved in the above-referred pathways with a summary of their applications in association studies. Because the supportive and opposing data have been reported in different populations, well-designed international collaborative studies need to be conducted to define the consistency of the associations, paving the way to better define the patients at high risk of developing cervical cancer.

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-23R polymorphisms, HBV infection, and risk of hepatocellular carcinoma in a high-risk Chinese population

BACKGROUND

The interleukin-23 receptor (IL-23R) plays an important role in the T-helper 17 cell-mediated inflammatory process and is also involved in tumor immune surveillance, which may be linked to carcinogenesis in hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC). In this study, we hypothesized that potentially functional genetic variants of the IL-23R gene may modify HCC risk.

METHODS

We genotyped two single-nucleotide polymorphisms (SNPs) of IL-23R, rs6682925 and rs1884444, in a case-control study of 837 HCC cases, 899 HBV surface antigen (HBsAg)-positive controls, and 743 HBsAg-negative controls. A reporter gene assay was performed to evaluate the functional relevance of the rs6682925 SNP located at the promoter region of the IL-23R gene.

RESULTS

We found that the two SNPs were associated with the risk of HCC when compared with both the HBsAg-positive and -negative controls. When compared with all controls, IL-23R rs6682925 and rs1884444 both increased the HCC risk in a recessive genetic model [rs6682925 CC vs. TT/TC: odds ratio (OR) 1.35, 95 % confidence interval (CI) 1.07-1.70; rs1884444 GG vs. TT/TG: OR 1.36, 95 % CI 1.05-1.77]. Furthermore, the variant C allele of rs6682925 in the promoter region of IL-23R was associated with increased reporter gene activity.

CONCLUSIONS

These findings indicate that genetic variants in IL-23R may contribute to HCC development.

TIM3 gene polymorphisms in patients with chronic hepatitis B virus infection: impact on disease susceptibility and hepatocellular carcinoma traits

Hepatitis B virus (HBV) infection is associated with the development of acute and chronic liver diseases including hepatocellular carcinoma (HCC). T-cell immunoglobulin domain and mucin domain-containing molecule-3 (Tim-3), which negatively regulates T-cell response and mediates phagocytosis of apoptotic cells, has been implicated in HBV infection and cancers. This study explored the polymorphisms of TIM3 gene in 535 patients with HBV-related liver diseases including 213 chronic hepatitis, 178 cirrhosis and 144 HCC, 72 HBV infection resolvers and 182 healthy controls and analyzed the effects of these polymorphisms on the disease susceptibility and HCC traits. TIM3-1541C/T, -1516G/T, -882C/T, -574G/T and +4259T/G polymorphisms were genotyped using polymerase chain reaction-restriction fragment length polymorphism. Of the five polymorphisms genotyped, the allele T-containing genotypes (GT + TT), allele T and allele T-containing haplotype (CTCGT) of -1516G/T polymorphism were more frequent in HBV patients than in controls [P = 0.005, odds ratio (OR) = 2.300, 95% confidence interval (CI): 1.294-4.088; P = 0.004, OR = 2.266, 95% CI: 1.297-3.962; and P = 0.005, OR = 2.203, 95% CI: 1.260-3.854, respectively]. The allele T-containing genotypes and allele T of -1516G/T were associated with HCC tumor grade (P = 0.023 and P = 0.017, respectively) and lymph node metastasis (P = 0.024 and P = 0.017, respectively). These findings suggest that -1516G/T polymorphism in the promoter region of TIM3 gene may affect the disease susceptibility and HCC traits associated with HBV infection, potentially supporting the role of Tim-3 in T-cell dysfunction and exhaustion involved in persistent HBV infection and HCC development.

Genetic risk of hepatocellular carcinoma in patients with hepatitis C virus: a case control study

BACKGROUND AND AIM

Chronic hepatitis C virus (HCV) infection is a well known risk factor for hepatocellular carcinoma (HCC). The aim of this study is to elucidate the genetic risk of development and recurrence of HCC in patients with HCV.

METHODS

A total of 468 patients with HCV, including 265 with HCC were enrolled. We genotyped 88 single nucleotide polymorphisms (SNPs) in 81 genes expected to influence hepatocarcinogenesis using the iPLEX assay. Risk of HCC was clarified by stratifying patients into risk groups based on the multiplied odds ratio (MOR) for SNPs associated with HCC, and the cumulative effects on the development and recurrence of HCC were analyzed.

RESULTS

Six SNPs associated with risk of HCC were identified (OR range: 0.29-1.76). These included novel SNPs for hepatocarcinogenesis with HCV CCND2 rs1049606, RAD23B rs1805329, CEP164 rs573455, and GRP78rs430397 in addition to the known SNPs MDM2 rs2279744 and ALDH2 rs671. MOR analysis revealed that the highest risk group exerted about a 19-fold higher relative OR compared with the lowest risk group (P = 1.08 × 10(-5)). Predicted 10-year HCC risk ranged from 1.7% to 96% depending on the risk group and the extent of fibrosis. Recurrence-free survival of radiofrequency ablation-treated HCC in the high risk group (n = 53) was lower than that of low risk group (n = 58, P = 0.038).

CONCLUSION

Single nucleotide polymorphisms of CCND2, RAD23B, GRP78, CEP164, MDM2, and ALDH2 genes were significantly associated with development and recurrence of HCC in Japanese patients with HCV.

A pilot study on cytotoxic T lymphocyte-4 gene polymorphisms in urinary schistosomiasis

Urinary schistosomiasis is caused by the digenetic trematode Schistosoma haematobium, characterized by accumulation of eggs in the genitourinary tract. Cytotoxic T-lymphocyte antigen 4 (CTLA-4) can play an important role in parasitic infection due to its major role as a negative regulator of T-cell activation and proliferation. This study was performed in patients with schistosomiasis and healthy controls to analyze the allele and genotype frequencies of four CTLA-4 gene polymorphisms. The CTLA-4 gene was amplified using Taqman real-time polymerase chain reaction, and allele and genotypes of 49 patients with schistosomiasis were analyzed using allelic discrimination analysis followed by subsequent direct sequencing. The results were compared with healthy control subjects. The frequencies of CTLA-4 rs733618 A allele at position -1722 (p=0.001), rs11571316 C allele at position -1577 (p<0.001), and rs231775 A allele at position +49 (p=0.002) in the patient group were significantly higher than the control group. The rs733618 AA genotype (p=0.001), rs11571316 CC genotype (p<0.001), and rs231775 AA genotype (p=0.007) were also significantly overrepresented. Meanwhile, rs733618 AG genotype (p=0.001), rs11571316 CT genotype (p=0.02), and rs231775 GG genotype (p=0.029) were significantly decreased in the patients with schistosomiasis, as compared with the controls. No significant difference was observed in both allele and genotype of rs16841252. The results of this study suggest that the rs733618, rs11571316, and rs231775 polymorphisms in the CTLA-4 gene may influence susceptibility to schistosomiasis infection in the Gabonese children.

Polymorphisms in the cytotoxic T-lymphocyte antigen 4 gene and cancer risk: a meta-analysis

BACKGROUND

Polymorphisms in the cytotoxic T-lymphocyte antigen 4 (CTLA-4) gene have been implicated in susceptibility to cancer, but the many published studies have reported inconclusive results. The objective of the current study was to conduct a meta-analysis investigating the association between polymorphisms in the CTLA-4 gene and the risk of cancer.

METHODS

The PubMed and EMBASE databases were searched for all articles published up to September 19, 2010 that addressed cancer and polymorphisms, variants, or mutations of CTLA-4. A statistical analysis was performed using proprietary statistical software.

RESULTS

Three polymorphisms (+49 adenine/guanine [+49A/G], -318 cytosine/thymine [-318C/T], and the +6230G/A polymorphism [CT60]) in 48 case-control studies from 27 articles were analyzed. The results indicated that individuals who carried the +49 G allele (AG + GG) had a 16% decreased risk of cancer compared with homozygotes (+49AA; odds ratio [OR], 0.84; 95% confidence interval [CI], 0.74-0.95). However, there was no significant association between the risk of cancer and the -318C/T polymorphism or the CT60 polymorphism (-318C/T: OR, 1.23; 95% CI, 0.99-1.54 for TT + TC vs CC; CT60: OR, 1.02; 95% CI, 0.80-1.29 for AA + AG vs GG). In further stratified analyses for the +49A/G and -318C/T polymorphisms, the decreased risk of cancer remained in subgroups of Europeans, patients with breast cancer, and patients with lung cancer for the +49A/G polymorphism; whereas an increased risk of cancer was observed among Europeans for the -318C/T polymorphism.

CONCLUSIONS

Results from the current meta-analysis suggested that the +49A/G and -318C/T polymorphisms in CTLA-4 are risk factors for cancer. To further evaluate gene-gene and gene-environment interactions between CTLA-4 polymorphisms and the risk of cancer, more studies with larger groups of patients will be required.

Epidermal growth factor +61 G/A polymorphism and the risk of hepatocellular carcinoma in a Chinese population

BACKGROUND

Chronic hepatitis B virus (HBV) infection is a risk factor of hepatocellular carcinoma (HCC) in China. Epidermal growth factor (EGF) plays an important role in tumorigenesis. The association between EGF +61 G/A polymorphism and the risk of HCC is still controversial and ambiguous.

AIM

The objective of this study was to investigate the association between EGF +61 G/A polymorphism and the risk of HCC in a Chinese population.

METHODS

A hospital-based case-control study was designed in a Chinese population. EGF +61 G/A polymorphisms were determined in 120 chronic HBV-infected HCC patients, 120 chronic HBV-infected cirrhotic patients, and 120 healthy controls. The genotype frequency of this polymorphism was determined by using a polymerase chain reaction-restriction fragment length polymorphism assay.

RESULTS

EGF +61 GG (odds ratio=2.76, 95% confidence interval=1.03, 7.38; p=0.04) and G allele frequencies (odds ratio=1.59, 95% confidence interval=1.08, 2.34; p=0.02) in the HCC group were higher than those in the cirrhosis group. EGF +61 A and G allele frequencies in healthy subjects were 28.8% and 71.2%. No relationship between EGF +61 G/A gene polymorphism and HCC risk was found among our recruited HCC patients and healthy controls.

CONCLUSION

This study suggests that EGF +61 GG genotype is associated with a higher risk of chronic HBV-infected HCC in the Chinese population.

Liver cancer epidemic in China: past, present and future

Primary liver cancer is the second most common malignancy, and currently results in 360,000 incident cases, and 350,000 deaths a year in China. For the past four decades, three national surveys on cancer mortality during the periods of 1973-1975, 1990-1992, and 2004-2005 have made it possible to estimate China's past and present liver cancer epidemic. The mortality rates of liver cancer were 17.6 and 7.3 per 100,000 for males and females in 1973-1975, 29.0 and 11.2 per 100,000 in 1990-1992, and 37.55 and 14.45 per 100,000 in 2004-2005, respectively. Recent monitoring from some regional cancer registries, which cover 5.7% of the total population in China, has revealed the distribution, disparities and trends of liver cancer in rural and urban areas. HBV and aflatoxins have been identified as major causal factors, that act individually and synergistically of liver cancer in the etiology. Other agents such as HCV, genetic susceptibility or genetic polymorphisms may also play important roles in the development of liver cancer. Great effort aimed at primary and Secondary prevention of this cancer, such as universal hepatitis B vaccination in children, chemoprevention in selected population, and early detection in at-risk population, has been undertaken. These strategies might be further emphasized in the future for the effective prevention of liver cancer in China.