Polymorphisms in the caspase-8 gene and the risk of lung cancer

c-Src Increases the Sensitivity to TKIs in the EGFR-Mutant Lung Adenocarcinoma

c-Src and the epidermal growth factor receptor (EGFR) are key apical kinases that govern cell responses to microenvironmental cues. How c-Src affects EGFR-related signaling and targeted therapy remains elusive. Initially, caspase-8 phosphorylated at tyrosine 380 by c-Src predominantly enhancing c-Src activation to facilitate metastasis through attaining epithelial-mesenchymal transition (EMT) phenotype in lung adenocarcinoma. Mechanistically, the linkage of c-Src SH2 domain with phosphotyrosine 380 of caspase-8 and SH3 domain with “PDEP” motif of caspase-8 overactivates c-Src as compared with other c-Src-partner proteins. c-Src is incapable of triggering EGFR-related signaling. This is reflected by the levels of phosphotyrosine 1068, 1086, and 1145, which have no impact on c-Src activation. Tyrosine kinase inhibitors (TKIs) suppress EGFR-related signaling to yield cell deaths of lung adenocarcinoma by both necroptosis and intrinsic apoptosis. Given that c-Src activation is frequent in lung adenocarcinoma, blocking c-Src activation through dasatinib can seal the survival-signaling-related phosphotyrosines of EGFR by its SH2 domain, which in turn increases the antitumor activity of TKIs in EGFR-mutant lung adenocarcinoma. Collectively, c-Src inactivation by dasatinib administration sensitizes EGFR-mutant lung adenocarcinoma to TKIs.

Intrinsic and extrinsic pathways of apoptosis: Role in cancer development and prognosis

Apoptosis, also named programmed cell death, is a fundament process required for morphogenetic homeostasis during early development and in pathophysiological conditions. It is come into existence in 1972 by work of Kerr, Wyllie and Currie and later on investigated during the research on development of the C. elegans. Trigger by several stimuli, apoptosis is necessary during the embryonic development and aging as homeostatic mechanism to control the cell population and also play a key role as defense mechanism against the immune responses and elimination of damaged cells. Cancer, a genetic disease, is a growing burden on the health and economy of both developing and developed countries. Every year there is tremendously increasing in the number of new cancer cases and mortality rate. Although, there is a significant improvement have been made in biotechnological and bioinformatic fields however, the therapeutic advantages and cancer etiology is still under explored. Several studies determined the deregulation of different apoptotic components during the cancer development and progression. Apoptosis relies on activation of distinct signaling pathways that are often deregulated in cancer. Thus, exploring the single or more than one apoptotic component underlying their expression in carcinogenesis could help to track the disease progression. Current book chapter will provide the several evidences supporting the use of different apoptotic components as prognosis and prediction markers in various human cancer types.

Polymorphisms in the Gene Encoding Caspase 8 May Predict the Response to First-Line Platinum-Based Chemotherapy in Locally Advanced or Advanced Non-Small-Cell Lung Cancer

Caspase 8 is a protein involved in the process of cell apoptosis, which may affect the efficacy of anti-cancer treatment. The aim of our study was to determine the impact of polymorphisms in the CASP-8 gene encoding caspase 8 on the prognosis in non-small-cell lung cancer (NSCLC). The study involved 99 patients with newly diagnosed locally advanced or metastatic NSCLC treated with platinum-based chemotherapy. The presence of the GG genotype was associated with distant metastases, smoking, and a family history of cancer. The higher risk of early progression was associated with weight loss and the CASP-8 genotype (GG vs. AG or AA: 20.51% vs. 2.86%). The higher risk of progression-free survival (PFS) shortening was associated with a higher stage of disease (hazard ratio (HR) = 2.50, 95% CI: 1.61–3.89, p < 0.0001), distant metastases (HR = 2.30, 95% CI: 1.42–3.72, p = 0.0016), and the GG genotype (HR = 1.68, 95% CI: 1.10–2.57, p = 0.0152). The influence of the GG genotype on the PFS was confirmed in a multivariate analysis (HR = 1.80, 95% CI: 1.06–3.05, p = 0.0317). We did not confirm the influence of CASP-8 genotypes on the overall survival (OS).

Genomic variants in Fas-mediated apoptosis pathway predict a poor response to Platinum-based Chemotherapy for Chinese Gastric Cancer Patients

Platinum-based adjuvant chemotherapy is very common for gastric cancer (GC) patients, but the chemotherapy sensitivity is very heterogeneous. The genomic variants and the gene-gene interactions involved in Fas-mediated apoptosis pathway including Fas (FAS 1377 G > A and 670 A > G), FasL (FASL 844 C > T) and caspase-8 (CASP8 -652 6N ins > del or I > D), may paly vital roles in the response to platinum-based treatment. In our investigation, 662 stage II-III postoperative GC patients were enrolled between 1998 and 2006. 261 patients accepted platinum-based regimens and the remaining 401 were not. The log rank tests, Kaplan Meier plots, Pearson chi-square tests, Student t-tests and Cox regression analyses were performed. For the chemotherapy cohort, FAS 1377 G > A or FAS 670 A > G variants alone was related with inferior survival, and a greater than additive effect was identified when patients simultaneously carrying FAS 1377 GA and FAS 670 GA genotypes. But the poor response was neutralized when patients simultaneously carrying FASL 844 C > T or CASP8 -652 6N ins > del mutations. Our study suggested that FAS 1377 G > A and FAS 670 A > G variants may serve as potential biomarkers to predict the response to platinum-based adjuvant chemotherapy, and the gene-gene interactions involved in Fas-mediated apoptosis pathway may enhance or neutralize the chemosensitivity.

Association of CASP8 polymorphisms and cancer susceptibility: A meta-analysis

Caspase-8 plays is an essential enzyme in apoptosis pathway. Several investigation have been done to identify the relation between CASP8 polymorphisms and different human cancers, but, the findings are still debated. The aim of the current investigation is to assess if CASP8 rs3834129 (-652 6N insertion/deletion), rs1045485 G > C, rs3769818 G > A, rs6723097 A > C, rs3769821 T > C, rs13113 T > A, rs3769825 G > A, rs2293554 A > C, and rs10931936 C > T polymorphisms are linked to susceptibility of cancer. Our team has extracted the eligible studies up to July 4, 2019, from different sources. Pooled odds ratios (ORs) with corresponding 95% confidence intervals (CIs) were estimated to quantitatively evaluate the association between CASP8 polymorphisms and cancer susceptibility. Our results showed that the rs3834129 and rs1045485 polymorphisms meaningfully reduced the risk of cancer, while the rs3769818, rs3769821 and rs3769825 polymorphisms considerably increased cancer susceptibility. No association of rs6723097, rs13113, rs2293554 and rs10931936 polymorphisms was observed with cancer susceptibility. The CASP8 rs3834129 polymorphism reduced the risk of gastrointestinal, digestive tract, colorectal, breast and lung cancers. Furthermore, the cancer risk was decreased in Asian and Caucasian populations as well as population- and hospital-based studies due to this polymorphism. There was not any relation between this gene polymorphism and the risk of prostate and cervical cancer development. Regarding the CASP8 rs1045485 polymorphism, the reduced breast cancer risk along with the risk of cancer in Caucasians, population- and hospital-based studies were observed.

Association of Caspase-8 Genotypes With Oral Cancer Risk in Taiwan

BACKGROUND/AIM

Recently, mounting evidence has shown that caspase-8 (CASP8) rs3834129 (-652, 6N insertion/deletion) polymorphism may serve as a genetic biomarker for personal risk of various cancer types. The contribution of CASP8 rs3834129 polymorphism has been investigated in several oral cancer populations, but not in Taiwan. This study investigated the role of CASP8 rs3834129 polymorphism on oral risk in Taiwan.

MATERIALS AND METHODS

CASP8 rs3834129 polymorphic genotypes were determined and their associations with oral cancer risk were investigated among 788 patients with oral cancer and 956 age- and gender-matched healthy controls via polymerase chain reaction-restrictive fragment length polymorphism (PCR-RFLP) methodology. In addition, the interaction of CASP8 rs3834129 genotype with personal behavior and clinicopathological features were also examined.

RESULTS

The frequencies of II, ID and DD genotypes for CASP8 rs3834129 were 57.5, 36.5 and 6.0% in the patient group and 54.0, 39.0 and 7.0% in the healthy control group, respectively (p for trend=0.3052), genotypes were not significantly differentially distributed between the two groups. The comparisons in allelic frequency distribution also supported the findings that the D variant allele may not serve as a determinant of risk for oral cancer. There was no interaction of CASP8 rs3834129 genotype with age, gender, smoking, alcohol or betel quid consumption in regard to oral cancer risk.

CONCLUSION

Our results indicate that the caspase-8 genotype does not appear to play a direct role in personal susceptibility to oral cancer in Taiwan.

Gene Combination of CD44 rs187116, CD133 rs2240688, NF-κB1 rs28362491 and GSTM1 Deletion as a Potential Biomarker in Risk Prediction of Breast Cancer in Lower Northern Thailand

Background:

Biomarkers play an important role in oncology, including risk assessment, treatment prediction, and monitoring the progression of disease. In breast cancer, many genes are used as biomarkers. Since, several SNP variations of hallmark – related genes have been reported to be of value in risk prediction in various cancers and populations, some genetic polymorphism loci were combined and reported as biomarkers for use in the risk assessment of breast cancer in Thai people.

Methods:

Twelve cancer gene hallmarks (15 polymorphic loci) were selected and genotyped in 184 breast cancer patients and 176 healthy individuals in Phitsanulok, Thailand.

Results:

AA genotype of CD44 rs187116 (c.67+4883G>A), the C allele of CD133 rs2240688 (c.*667A>C), the *2 allele (4 bp deletion) of NF-κB1 rs28362491 and the homozygous null allele genotype of GSTM1 were significantly associated with an increased risk of breast cancer (p<0.05). A combination of these 4 significant loci showed that AA-AA-*1*1-homozygous null allele genotype has the greatest correlation with increased risk of breast cancer (OR = 21.00; 95% CI: 1.77 to 248.11; p = 0.015), followed by GA-AA-*2*2- homozygous null allele genotype (p = 0.037) and GG-AC-*1*2- homozygous null allele genotype (p = 0.028).

Conclusion:

These findings suggest that the polymorphisms of CD44 rs187116 (c.67+4883G>A), CD133 rs2240688 (c.*667A>C), NF-κB1 rs28362491 and GSTM1 homozygous null allele genotype might be associated with an increased risk of breast cancer, and this gene combination could possibly be used as biomarkers for risk prediction, which would be of benefit in planning health surveillance and cancer prevention.

Caspase 8 polymorphisms contribute to the prognosis of advanced lung adenocarcinoma patients after platinum-based chemotherapy

Lung cancer is the leading cause of cancer deaths in China, and about 60% of the cases are diagnosed with histological adenocarcinoma. The caspase 8 (CASP8) gene is a critical initiator of the extrinsic apoptosis pathway. To explore the relationship between tagSNPs or haplotypes of CASP8 and the efficacy of platinum-based chemotherapy in advanced lung adenocarcinoma patients of China, we recruited 555 advanced adenocarcinoma patients. We extracted the genomic DNA from patients' peripheral blood samples and sequenced tagSNPs of CASP8. We calculated the individual haplotype of CASP8 frequencies using the PHASE 2.0 program. The association between CASP8 tagSNPs and overall survival (OS) was calculated by univariate and multivariate Cox regression analysis. A univariate logistic regression analysis was done to analyze the CASP8 tagSNPs and the toxicity of platinum-based chemotherapy. The same statistical methods were used for exploring haplotypes of CASP8. Rs3769821 and rs1045494 of CASP8 were independent prognosis factors for overall survival (OS) using multivariate Cox's regression models. For the haplotype of the 7 tagSNPs, haplotype AGGAAAGA was correlated with the efficacy of platinum-based chemotherapy. The polymorphisms of CASP8, rs7608692, and haplotype AGAACAG correlated with neutropenia toxicity. The haplotype GGGGAAA was associated with thrombocytopenia toxicity. We conclude that the polymorphisms of CASP8 contribute to the prognosis of advanced lung adenocarcinoma and influence the quality of life and survival.

Shared susceptibility loci at 2q33 region for lung and esophageal cancers in high-incidence areas of esophageal cancer in northern China

Background

Cancers from lung and esophagus are the leading causes of cancer-related deaths in China and share many similarities in terms of histological type, risk factors and genetic variants. Recent genome-wide association studies (GWAS) in Chinese esophageal cancer patients have demonstrated six high-risk candidate single nucleotide polymorphisms (SNPs). Thus, the present study aimed to determine the risk of these SNPs predisposing to lung cancer in Chinese population.

Methods

A total of 1170 lung cancer patients and 1530 normal subjects were enrolled in this study from high-incidence areas for esophageal cancer in Henan, northern China. Five milliliters of blood were collected from all subjects for genotyping. Genotyping of 20 high-risk SNP loci identified from genome-wide association studies (GWAS) on esophageal, lung and gastric cancers was performed using TaqMan allelic discrimination assays. Polymorphisms were examined for deviation from Hardy-Weinberg equilibrium (HWE) using Х² test. Bonferroni correction was performed to correct the statistical significance of 20 SNPs with the risk of lung cancer. The Pearson’s Х² test was used to compare the distributions of gender, TNM stage, histopathological type, smoking and family history by lung susceptibility genotypes. Kaplan-Meier and Cox regression analyses were carried out to evaluate the associations between genetic variants and overall survival.

Results

Four of the 20 SNPs identified as high-risk SNPs in Chinese esophageal cancer showed increased risk for Chinese lung cancer, which included rs3769823 (OR = 1.26; 95% CI = 1.107–1.509; P = 0.02), rs10931936 (OR = 1.283; 95% CI = 1.100–1.495; P = 0.04), rs2244438 (OR = 1.294; 95% CI = 1.098–1.525; P = 0.04) and rs13016963 (OR = 1.268; 95% CI = 1.089–1.447; P = 0.04). All these SNPs were located at 2q33 region harboringgenes of CASP8, ALS2CR12 and TRAK2. However, none of these susceptibility SNPs was observed to be significantly associated with gender, TNM stage, histopathological type, smoking, family history and overall survival.

Conclusions

The present study identified four high-risk SNPs at 2q33 locus for Chinese lung cancer and demonstrated the shared susceptibility loci at 2q33 region for Chinese lung and esophageal cancers.

Tyrosine Phosphorylation of Caspase-8 Abrogates Its Apoptotic Activity and Promotes Activation of c-Src

Src family tyrosine kinases (SFKs) phosphorylate caspase-8A at tyrosine (Y) 397 resulting in suppression of apoptosis. In addition, the phosphorylation of caspase-8A at other sites including Y465 has been implicated in the regulation of caspase-8 activity. However, the functional consequences of these modifications on caspase-8 processing/activity have not been elucidated. Moreover, various Src substrates are known to act as potent Src regulators, but no such role has been explored for caspase-8. We asked whether the newly identified caspase-8 phosphorylation sites might regulate caspase-8 activation and conversely, whether caspase-8 phosphorylation might affect Src activity. Here we show that Src phosphorylates caspase-8A at multiple tyrosine sites; of these, we have focused on Y397 within the linker region and Y465 within the p12 subunit of caspase-8A. We show that phosphomimetic mutation of caspase-8A at Y465 prevents its cleavage and the subsequent activation of caspase-3 and suppresses apoptosis. Furthermore, simultaneous phosphomimetic mutation of caspase-8A at Y397 and Y465 promotes the phosphorylation of c-Src at Y416 and increases c-Src activity. Finally, we demonstrate that caspase-8 activity prevents its own tyrosine phosphorylation by Src. Together these data reveal that dual phosphorylation converts caspase-8 from a pro-apoptotic to a pro-survival mediator. Specifically, tyrosine phosphorylation by Src renders caspase-8 uncleavable and thereby inactive, and at the same time converts it to a Src activator. This novel dynamic interplay between Src and caspase-8 likely acts as a potent signal-integrating switch directing the cell towards apoptosis or survival.

CASP-1, -2 and -5 gene polymorphisms and cancer risk: A review and meta-analysis

Accumulating evidence suggests the CASP gene family is important in the development of carcinogenesis. These genetic polymorphisms have been extensively investigated as a potential risk factor for cancer, but results have been inconclusive. This Human Genome Epidemiology (HuGE) review and meta-analysis was performed to investigate the associations between CASP-1, -2 and -5 and cancer risk. A literature search of Pubmed, Embase, Web of Science and CBM databases was conducted from inception through September 1st, 2012. Four case-control studies with a total of 1,592 cancer cases and 1,833 healthy controls were included in the present meta-analysis. Crude odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of association. Five polymorphisms were examined, including rs501192 (G>A), rs4647297 (C>G), rs507879 (T>C), rs3181320 (G>C) and rs523104 (G>C). Meta-analysis results showed that the rs3181320*C allele/carrier were associated with increased risk of various types of cancers (OR=1.26; 95% CI, 1.04-1.54; P=0.020 and OR=1.33; 95% CI, 1.00-1.75; P=0.047, respectively). However, similar associations were not found in the rs501192, rs4647297, rs507879 and rs523104 polymorphisms (all P>0.05). Results from the current meta-analysis suggest that the rs3181320*C allele/carrier in CASP-5 gene are potential risk factors for cancer.

CASP8 promoter polymorphism, mRNA expression and risk of prostate cancer among Chinese men

Caspase-8 (CASP8) plays a key role in apoptosis. We examined by genotyping whether the -652 six-nucleotide insertion-deletion (6N ins/del) polymorphism in the CASP8 promoter region was associated with prostate cancer risk in a hospital-based case-control study of 406 Chinese prostate cancer patients and 408 age-matched cancer-free controls. Additionally, 23 prostate cancer tissues were analyzed for CASP8 mRNA expression. We found a significantly decreased prostate cancer risk for the 6N ins/del genotype [adjusted odds ratio (OR)=0.68; 95% confidence interval (CI)=0.51-0.92] and del/del genotype (OR=0.34; 95% CI=0.19-0.63) compared with the ins/ins genotype. The 6N del allele was associated dose-dependently with decreased prostate cancer risk (P_trend = 0.001). RT-PCR showed that individuals with the 6N del allele had lower CASP8 mRNA levels than those with the ins/ins genotype (P = 0.024). These findings suggested that the CASP8-652 6N ins/del polymorphism may affect the susceptibility to prostate cancer and reduce prostate cancer risk among Chinese men.

Role of the CASP-9 Ex5+32 G>A polymorphism in susceptibility to cancer: A meta-analysis

Failure of apoptosis is one of the hallmarks of cancer. As an execution-phase caspase, caspase-9 plays a crucial role during apoptosis. To examine whether the Ex5+32 G>A (rs1052576) polymorphism in the CASP-9 gene alters cancer risk, we conducted a comprehensive meta-analysis of 7 case-control studies consisting of a total of 1668 cancer cases and 2294 healthy controls. All studies considered, A allele and A allele carriers of Ex5+32 G>A in the CASP-9 gene had significant associations with cancer risk (OR=0.72, 95% CI, 0.58–0.89, P= 0.003; OR= 0.76, 95% CI, 0.63–0.92, P= 0.004; respectively). In the subgroup analysis, we found that the A allele of Ex5+32 G>A was a protective factor for cancer risk in Chinese and American populations (OR=0.60, 95% CI, 0.44–0.81, P<0.001; OR= 0.80, 95% CI, 0.69–0.94, P= 0.005; respectively). Similarly, we also found positive associations between A allele carriers of Ex5+32 G>A and cancer risk in Chinese and American populations (OR=0.63, 95% CI, 0.44–0.90, P= 0.01; OR= 0.78, 95% CI, 0.62–0.98, P=0.03; respectively). In addition, we identified that A allele and A allele carriers of Ex5+32 G>A may decrease the risk of cancer in the Asian population (OR=0.60, 95% CI, 0.44–0.81, P<0.001; OR= 0.63, 95% CI, 0.44–0.90, P= 0.01; respectively). In conclusion, this meta-analysis demonstrated that A allele and A allele carriers of the Ex5+32 G>A polymorphism in the CASP-9 gene may be protective factors for cancer risk.

A six-nucleotide deletion polymorphism in the casp8 promoter is associated with reduced risk of esophageal and gastric cancers in Kashmir valley

BACKGROUND:

Caspase-8 (CASP8) is a key regulator of apoptosis or programmed cell death, an essential defense mechanism against hyperproliferation and malignancy. To evaluate the role of CASP8 polymorphisms in esophageal (EC) and gastric cancers (GC) in the Kashmir valley, we examined the risk due to -652 6N ins/del polymorphism (rs3834129) in the promoter of CASP8 in a case–control study.

MATERIALS AND METHODS:

Genotypes of the CASP8 polymorphisms (-652 6N ins/del; rs3834129) were determined for 315 patients (135 EC and 108 GC) and 195 healthy controls by polymerase chain reaction. Data was statistically analyzed using Chi-square test and logistic regression model by using the SPSS software.

RESULTS:

Carriers for the del allele of rs3834129 single nucleotide polymorphism were associated with decreased risk for both EC (odds ratio [OR] = 0.278; 95% confidence interval [95% CI] = 0.090–0.853; P = 0.025) and GC (OR = 0.397; 95% CI = 0.164–0.962; P = 0.041). Also, in a recessive model, our results showed that CASP8 -652 6N ins/del “del/del” allele was conferring significant low risk for both EC (OR = 0.380; 95% CI = 0.161–0.896; P = 0.027) and GC (OR = 0.293; 95% CI = 0.098–0.879; P = 0.029). However, interaction of CASP8 -652 6N ins/del genotypes with smoking and high consumption of salted tea did not further modulate the risk of EC and GC.

CONCLUSIONS:

Polymorphism in CASP8 -652 6N ins/del polymorphism modulates the risk of EC and GC in Kashmir valley.

CASP-8 -652 6N ins/del polymorphism and cancer risk: A literature-based systematic HuGE review and meta-analysis

Caspase-8 (encoded by the CASP-8 gene) is crucial in generating cell death signals and eliminating potentially malignant cells. Genetic variation in CASP8 may affect susceptibility to cancer. The CASP-8 −652 6N ins/del (rs3834129) polymorphism has been previously reported to influence the progression to several cancers. However, the overall reported studies have shown inconsistent conclusions. In this human genome epidemiology (HuGE) review and meta-analysis, the aim was to identify the association between CASP-8 −652 6N ins/del polymorphism and cancer risk. According to the inclusion criteria, 19 case-control studies with a total of 23,172 cancer cases and 26,532 healthy controls were retrieved. Meta-analysis results showed that the del allele, del allele carrier and ins/del genotype of −652 6N ins/del in the CASP-8 gene were negatively associated with cancer risk (OR=0.91, 95% CI=0.84–0.98, P=0.01; OR=0.88, 95% CI=0.80–0.96, P=0.005; OR=0.91, 95% CI=0.85–0.98, P<0.001; respectively, while no significant correlation was observed between the del/del genotype of −652 6N ins/del and cancer risk (OR=0.89, 95% CI=0.79–1.01, P=0.08). In the subgroup analysis by ethnicity, the meta-analysis indicated that Caucasian populations harboring the del allele, del allele carriers and ins/del genotype had a lower cancer risk (OR=0.96, 95% CI=0.93–1.00, P=0.05; OR=0.86, 95% CI=0.75–1.00, P=0.05; OR=0.91, 95% CI=0.84–0.98, P=0.01; respectively). In addition, a negative association was found between the del allele of −652 6N ins/del in the CASP-8 gene and cancer risk in the Asian population (OR=0.89, 95% CI=0.83–0.97, P=0.005). In conclusion, this meta-analysis suggests that the del allele, del allele carrier and ins/del geno-type of the −652 6N ins/del polymorphism in the CASP-8 gene may be protective factors for cancer risk.

Systematic evaluation of apoptotic pathway gene polymorphisms and lung cancer risk

We adopted a two-stage study design to screen 927 single nucleotide polymorphisms (SNPs) located in 73 apoptotic-pathway genes in a case-control study and then performed a fast-track validation of the significant SNPs in a replication population to identify sequence variations in the apoptotic pathway modulating lung cancer risk. Fifty-five SNPs showed significant associations in the discovery population comprised of 661 lung cancer cases and 959 controls. Six of these SNPs located in three genes (Bcl-2, CASP9 and ANKS1B) were validated in a replication population with 1154 cases and 1373 controls. Additive model was the best-fitting model for five SNPs (rs1462129 and rs255102 of Bcl-2, rs6685648 of CASP9 and rs1549102, rs11110099 of ANKS1B) and recessive model was the best fit for one SNP (rs10745877 of ANKS1B). In the analysis of joint effects with subjects carrying no unfavorable genotypes as the reference group, those carrying one, two, and three or more unfavorable genotypes had an odds ratio (OR) of 2.22 [95% confidence interval (CI) = 1.08-4.57, P = 0.03], 2.70 (95% CI = 1.33-5.49; P = 0.006) and 4.13 (95% CI = 2.00-8.57; P = 0.0001), respectively (P for trend = 6.05E-06). The joint effect of unfavorable genotypes was also validated in the replication population. The SNPs identified are located in or near key genes known to play important roles in apoptosis regulation, supporting the strong biological relevance of our findings. Future studies are needed to identify the causal SNPs and elucidate the underlying molecular mechanisms.

Prognostic Impact of Polymorphisms in the CASPASE Genes on Survival of Patients with Colorectal Cancer

Purpose

This study analyzed potentially functional polymorphisms in CASPASE (CASP) genes and their impact on the prognosis for Korean colorectal cancer patients.

Materials and Methods

A total of 397 consecutive patients with curatively resected colorectal adenocarcinoma were enrolled in this study. Genomic DNA from these patients was extracted from fresh colorectal tissue, and the 10 polymorphisms in the CASP3, CASP6, CASP7, CASP8, CASP9, and CASP10 genes were determined using a reverse transcription polymerase chain reaction genotyping assay.

Results

The median patient age was 63 years, and 218 (54.9%) patients had colon cancer, while 179 (45.1%) patients had rectal cancer. Univariate and multivariate survival analysis including pathologic stage, patient age, differentiation, and carcinoembryonic antigen level demonstrated that these polymorphisms were not associated with either disease-free or overall survival.

Conclusion

None of the 10 polymorphisms in the CASP genes investigated in this study was found to be an independent prognostic marker for Korean patients with curatively resected colorectal cancer.

Genotypic variants at 2q33 and risk of esophageal squamous cell carcinoma in China: a meta-analysis of genome-wide association studies

Genome-wide association studies have identified susceptibility loci for esophageal squamous cell carcinoma (ESCC). We conducted a meta-analysis of all single-nucleotide polymorphisms (SNPs) that showed nominally significant P-values in two previously published genome-wide scans that included a total of 2961 ESCC cases and 3400 controls. The meta-analysis revealed five SNPs at 2q33 with P< 5 × 10(-8), and the strongest signal was rs13016963, with a combined odds ratio (95% confidence interval) of 1.29 (1.19-1.40) and P= 7.63 × 10(-10). An imputation analysis of 4304 SNPs at 2q33 suggested a single association signal, and the strongest imputed SNP associations were similar to those from the genotyped SNPs. We conducted an ancestral recombination graph analysis with 53 SNPs to identify one or more haplotypes that harbor the variants directly responsible for the detected association signal. This showed that the five SNPs exist in a single haplotype along with 45 imputed SNPs in strong linkage disequilibrium, and the strongest candidate was rs10201587, one of the genotyped SNPs. Our meta-analysis found genome-wide significant SNPs at 2q33 that map to the CASP8/ALS2CR12/TRAK2 gene region. Variants in CASP8 have been extensively studied across a spectrum of cancers with mixed results. The locus we identified appears to be distinct from the widely studied rs3834129 and rs1045485 SNPs in CASP8. Future studies of esophageal and other cancers should focus on comprehensive sequencing of this 2q33 locus and functional analysis of rs13016963 and rs10201587 and other strongly correlated variants.

Single nucleotide polymorphisms as susceptibility, prognostic, and therapeutic markers of nonsmall cell lung cancer

Lung cancer is a major public health problem throughout the world. Among the most frequent cancer types (prostate, breast, colorectal, stomach, lung), lung cancer is the leading cause of cancer-related deaths worldwide. Among the two major subtypes of small cell lung cancer and nonsmall cell lung cancer (NSCLC), 85% of tumors belong to the NSCLC histological types. Small cell lung cancer is associated with the shortest survival time. Although tobacco smoking has been recognized as the major risk factor for lung cancer, there is a great interindividual and interethnic difference in risk of developing lung cancer given exposure to similar environmental and lifestyle factors. This may indicate that in addition to chemical and environmental factors, genetic variations in the genome may contribute to risk modification. A common type of genetic variation in the genome, known as single nucleotide polymorphism, has been found to be associated with susceptibility to lung cancer. Interestingly, many of these polymorphisms are found in the genes that regulate major pathways of carcinogen metabolism (cytochrome P450 genes), detoxification (glutathione S-transferases), adduct removal (DNA repair genes), cell growth/apoptosis (TP53/MDM2), the immune system (cytokines/chemokines), and membrane receptors (nicotinic acetylcholine and dopaminergic receptors). Some of these polymorphisms have been shown to alter the level of mRNA, and protein structure and function. In addition to being susceptibility markers, several of these polymorphisms are emerging to be important for response to chemotherapy/radiotherapy and survival of patients. Therefore, it is hypothesized that single nucleotide polymorphisms will be valuable genetic markers in individual-based prognosis and therapy in future. Here we will review some of the most important single nucleotide polymorphisms in the metabolic pathways that may modulate susceptibility, prognosis, and therapy in NSCLC.

Lung Cancer: Are we up to the Challenge?

Lung cancer is the leading cause of cancer deaths worldwide among both men and women, with more than 1 million deaths annually. Non–small cell lung cancer (NSCLC) accounts for about 80% of all lung cancers.

Although recent advances have been made in diagnosis and treatment strategies, the prognosis of NSCLC patients is poor and it is basically due to a lack of early diagnostic tools.

However, in the last years genetic and biochemical studies have provided more information about the protein and gene’s mutations involved in lung tumors. Additionally, recent proteomic and microRNA’s approaches have been introduced to help biomarker discovery.

Here we would like to discuss the most recent discoveries in lung cancer pathways, focusing on the genetic and epigenetic factors that play a crucial role in malignant cell proliferation, and how they could be helpful in diagnosis and targeted therapy.

Polymorphisms in the CASP8 gene and the risk of epithelial ovarian cancer

OBJECTIVE

The CASP8 gene plays a central role in the apoptotic pathway and is therefore a plausible cancer susceptibility gene. However, the precise role of the CASP8 gene in epithelial ovarian cancer carcinogenesis is unclear. Therefore, we analyzed the correlation between single nucleotide polymorphisms (SNPs) and haplotypes in CASP8 and the risk and clinical characteristics of epithelial ovarian cancer (EOC) in the Chinese population.

SUBJECTS AND METHODS

Eight tag SNPs were identified using the MassARRAY system to genotype 37 genetic polymorphisms around and in the CASP8 gene in 100 unrelated, healthy females. Then, a case-control study of 218 EOC patients and 285 controls who were matched on residence, age and race was conducted using these 8 tag SNPs.

RESULTS

The risk of developing EOC was significantly decreased in association with CASP8 rs3834129 ins>del (odds ratio (OR)(del/del)=0.129, 95% confidence interval (95% CI): 0.038-0.439; OR(ins/del)=0.769, 95% CI, 0.534-1.108), rs3769827 T>C (OR(C/C)=0.187, 95% CI: 0.070-0.500; OR(T/C)=0.729, 95% CI: 0.505-1.052), rs6704688 C>T (OR(T/T)=0.344, 95% CI, 0.168-0.707; OR(C/T)=0.802, 95% CI, 0.552-1.166), and with the del-C-T haplotype of these 3 SNPs (OR=0.615, 95% CI: 0.453-0.8363). Moreover, a notably later onset was significantly associated with the rs3834129 ins/del+del/del and the rs3769827 T/C+C/C genotypes (p<0.0001).

CONCLUSIONS

Genetic variants of the CASP8 gene protect against EOC carcinogenesis and delay the age of EOC onset. Furthermore, these protective effects may be due to the dysfunctional expression of caspase-8 caused by the -652 6N del variant in the promoter.

Polymorphisms and haplotypes in caspases 8 and 9 genes and risk for prostate cancer: a case-control study in cohort of North India

OBJECTIVE

Despite the potential importance of apoptosis pathways in prostate tumor etiology, little has been published regarding prostate tumor risk associated with common gene variants in caspases (CASP). Normal variations within the sequence of apoptotic genes may lead to suboptimal apoptotic capacity and therefore increased cancer risk.

MATERIALS AND METHODS

Using data from a hospital-based case-control study conducted by Sanjay Gandhi Post Graduate Institute of Medical Science, India, from 2007 to 2009, we evaluated risk of prostate cancer (CaP) in 165 patients and age-matched 205 healthy controls. We genotyped the functional IVS12-19G/A, D302H, -678del, and -652 6N ins/del polymorphisms in the promoter of CASP 8 and -293del, -1263A/G in CASP 9 genes.

RESULTS

A significant increased risk for CaP was found for the CASP 8 IVS12-19G/A heterozygous genotype (P = 0.02; OR = 1.69) as well as for the variant allele carriers (P = 0.04; OR = 1.56). Also the CASP 9 -1263A/G showed lower risk for both heterozygous and variant allele carrier genotypes (P = 0.002; OR = 0.45 and P = 0.05; OR = 0.66 respectively). CASP 9 -1263A/G was also found to be associated with increased risk with bone metastasis. Furthermore, a significant additive interaction between CASP 8 IVS12-19G/A polymorphism and tobacco smoking was observed with CaP risk.

CONCLUSION

These results suggested that the CASP 8 IVS12-19G/A and CASP 9 -1263 polymorphism may be involved in etiology of CaP and thus could be implicated as a marker for genetic susceptibility in North Indian population.

CASP8 -652 6N del and CASP8 IVS12-19G>A gene polymorphisms and susceptibility/prognosis of ESCC: a case control study in northern Indian population

BACKGROUND

Caspase8 influences carcinogenesis through regulation of apoptosis, hyperproliferation, and metastasis. Role of genetic variations in caspase8 has been explored in various cancers; however, their predictive and prognostic role in esophageal cancer is poorly understood.

METHODS

We investigated the association of two potential caspase8 polymorphisms: CASP8 -652 6N del and CASP8 IVS12-19 G>A polymorphisms with susceptibility and survival of 259 esophageal squamous cell carcinoma (ESCC) cases and 259 cancer-free controls from northern Indian population using PCR/PCR RFLP method.

RESULTS

CASP8 IVS12-19 AA genotype was found to be associated with significant increased risk of ESCC (odds ratio (OR) 3.28, 95% confidence interval (CI) 1.04-10.29) specifically in male subjects (OR 3.71, 95% CI 1.01-13.35) with lower third tumor anatomical location (OR 6.00, 95% CI 1.60-22.55). Kaplan-Meier and Cox Regression analysis showed lower median survival (7.13 months vs. 25.21 months) and greater hazard of death (HR 3.40, 95% CI 1.38-7.90) with CASP8 IVS12-19 AA genotype in ESCC cases compared to IVS12-19 GG genotype. However, no association of CASP8 -652 6N del polymorphism with susceptibility and prognosis of ESCC was observed.

CONCLUSION

CASP8 IVS12-19 G>A but not CASP8 -652 6N del polymorphism may modulate risk of ESCC and its survival outcome in northern Indian population.

Caspase 8 gene variants in healthy North Indian population and comparison with worldwide ethnic group variations

BACKGROUND:

Many strategies are being used for the quest for the disease causing genes. Inter-individual variations in several genes exist. Thus, even if they share the same disease-associated allele, the genomic backgrounds – and hence potential interacting alleles at other loci – of people with different regional ancestries may differ, with a consequent variation in the severity of their disease.

MATERIALS AND METHOD:

The present study was conducted to determine the distribution of Caspase 8 IVS12-19G/A, Caspase 8D302H, Caspase 8 -652del and Caspase 8 -678del polymorphisms (as frequency distribution of caspases in Indians generally is not yet known), which was then compared with different populations globally. Polymerase chain reaction (PCR)-based analysis was conducted in 205 normal healthy individuals of similar ethnicity.

RESULTS:

The variant allele frequencies were 17.6% (A) in Caspase 8 IVS12-19G/A, 13.2% (H) in Caspase 8D302H, 23.2% (Del) in Caspase 8 -652del and 24.6% (Del) in Caspase 8 -678del. Further, comparison of frequency distribution of these genes was done with various published studies of different ethnic groups globally.

CONCLUSION:

It is anticipated from our results that the frequency of these caspase genes exhibits distinctive patterns in India, which could perhaps be attributed to ethnic variation. This study is important as it can form a baseline for screening individuals who are at high risk due to exposure to environmental carcinogens and cancer predisposition, and therefore, might help in investigating linked polymorphisms in a way that will not obscure potential associations between genotype and phenotype.

Association of the variants CASP8 D302H and CASP10 V410I with breast and ovarian cancer risk in BRCA1 and BRCA2 mutation carriers

BACKGROUND

The genes caspase-8 (CASP8) and caspase-10 (CASP10) functionally cooperate and play a key role in the initiation of apoptosis. Suppression of apoptosis is one of the major mechanisms underlying the origin and progression of cancer. Previous case-control studies have indicated that the polymorphisms CASP8 D302H and CASP10 V410I are associated with a reduced risk of breast cancer in the general population.

METHODS

To evaluate whether the CASP8 D302H (CASP10 V410I) polymorphisms modify breast or ovarian cancer risk in BRCA1 and BRCA2 mutation carriers, we analyzed 7,353 (7,227) subjects of white European origin provided by 19 (18) study groups that participate in the Consortium of Investigators of Modifiers of BRCA1/2 (CIMBA). A weighted cohort approach was used to estimate hazard ratios (HR) and 95% confidence intervals (95% CI).

RESULTS

The minor allele of CASP8 D302H was significantly associated with a reduced risk of breast cancer (per-allele HR, 0.85; 95% CI, 0.76-0.97; P(trend) = 0.011) and ovarian cancer (per-allele HR, 0.69; 95% CI, 0.53-0.89; P(trend) = 0.004) for BRCA1 but not for BRCA2 mutation carriers. The CASP10 V410I polymorphism was not associated with breast or ovarian cancer risk for BRCA1 or BRCA2 mutation carriers.

CONCLUSIONS

CASP8 D302H decreases breast and ovarian cancer risk for BRCA1 mutation carriers but not for BRCA2 mutation carriers.

IMPACT

The combined application of these and other recently identified genetic risk modifiers could in the future allow better individual risk calculation and could aid in the individualized counseling and decision making with respect to preventive options in BRCA1 mutation carriers.

From procaspase-8 to caspase-8: revisiting structural functions of caspase-8

Caspase-8 is well-characterized to initiate an apoptotic pathway triggered by the external stimuli. The proximity-driven model recently has been proposed to interpret the activation mechanism of caspase-8 in so-far unprecedent detail, in which dimerization, autocleavage, and inhibitor of caspase-8 are indispensable. Intriguingly, death effector domains (DEDs) and ubiquitination after active caspase-8 is released into cytosol can also promote cell apoptosis indirectly. In addition to the proapoptotic role of caspase-8, there is emerging evidence to indicate that the precursor of caspase-8, procaspase-8, has an important function in cell adhesion and migration. Phosphorylation of caspase-8 by c-src controls these functions by preventing the conversion of procaspase-8 to caspase-8. This provides a mechanism to switch these opposing functions. In the migratory role, procaspase-8 interacts with the phosphatidylinositol-3-OH kinase (PI3K) regulatory subunit p85alpha and c-src to modulate signaling by Rac and extracellular signal-regulated kinase (ERK) 1/2, and promotes calpain2 activation. Here, the focus of this review is to highlight three respective aspects of caspase-8, including precursor functions, activation mechanism and maintenance of activity.

Effects of caspase-9 and survivin gene polymorphisms in pancreatic cancer risk and tumor characteristics

OBJECTIVES

This case-control study was performed to evaluate the association between a specific caspase-9 polymorphism as well as the genetic polymorphism -31G/C located in the cycle-dependent elements/cell cycle homology regions repressor element of the human survivin promoter and the risk of pancreatic cancer.

METHODS

Eighty patients with pancreatic cancer and 160 healthy controls were investigated for genotype and allelic frequencies of caspase-9 1263A/G and survivin -31G/C polymorphisms by Polymerase Chain Reaction-Restriction Fragment Length Polymorphism.

RESULTS

The G carrier group of patients and the G allele of caspase-9 1263A/G were overrepresented among the pancreatic cancer cases. With regard to tumor characteristics, a statistically significant association was detected between the survivin C carrier group of patients and the advanced T stage as well as the presence of lymph node metastasis.

CONCLUSIONS

The caspase-9 G allele confers increased susceptibility to pancreatic cancer development, and the survivin C carriage status may be related to aggressive features of this malignancy.

Functional polymorphisms in cell death pathway genes and risk of renal cell carcinoma

The FAS/FAS ligand (FASL) system plays a key role in regulating apoptotic cell death, and corruption of this signaling pathway has been shown to participate in tumorigenesis. However, the effects of functional promoter polymorphisms of the CASP8, FAS, and FASL genes on risk of renal cell carcinoma (RCC) are unknown. In this study, we genotyped CASP8 -652 6N ins/del, FAS -1377 G > A, FAS -670 A > G, and FASL -844 C > T polymorphisms in a hospital-based case-control study of 353 patients diagnosed with RCC and 365 cancer-free controls in a Chinese population. Compared with CASP8 -652 ins/ins genotype, the del/del genotype had a significantly decreased RCC risk [adjusted odds ratio (OR) = 0.36, 95% confidence interval (CI) = 0.16-0.84]. For FAS -1377 G > A polymorphism, a significantly increased risk of RCC was found for AA (adjusted OR = 1.65, 95% CI = 1.03-2.64) and GA (adjusted OR = 1.41, 95% CI = 1.02-1.94) genotypes compared with GG genotype. When we combined these two polymorphisms together, we found that individuals carrying CASP8 -652 6N ins/del and FAS -1377 GG genotypes or CASP8 -652 6N del/del and FAS -1377 GG genotypes were associated with a statistically significantly decreased risk of RCC (adjusted OR = 0.46, 95% CI = 0.24-0.88 and OR = 0.12, 95% CI = 0.02-0.58, respectively) compared with individuals carrying CASP8 -652 6N ins/ins and FAS -1377 AA genotypes. These results suggest that the CASP8 -652 6N ins/del and FAS -1377 G > A polymorphisms are involved in the susceptibility to developing RCC in Chinese populations.

Caspase-8 polymorphisms and risk of gallbladder cancer in a northern Indian population

Caspase-8 (CASP8) is a key controller of apoptosis, and its deregulation plays an important role in carcinogenesis. To evaluate the role of CASP8 polymorphisms in gallbladder cancer (GBC), we examined the risk associated with three single-nucleotide polymorphisms (SNPs) in a case-control study in North Indian population. Genotypes and haplotypes of the CASP8 polymorphisms (-652 6N ins/del; rs3834129, Ex13 + 51G > C; rs1045485 and IVS12-19 G > A; rs3769818) were determined for 230 GBC patients and 230 cancer-free controls randomly selected from the population. Odds ratio (OR) and 95% confidence interval (95% CI) were calculated in multivariate logistic regression analysis for the association of individual SNPs and haplotypes with GBC. Carriers for the "del" allele of rs3834129 SNP were associated with a 0.60-fold decreased risk for GBC (95% CI = 0.42-0.88; P(trend) = 0.005). In the combined analysis of the three CASP8 variants, we found that the individuals with the diplotypes carrying two copies of the common CASP8 del-G-G haplotype had 0.35-fold reduced risk (95% CI = 0.14-0.85) when compared with the diplotype containing 0-1 copy. The false-positive report probability (FPRP) approach advocated that these results were noteworthy (FPRP < 0.5). The molecular modeling results of rs1045485 polymorphism indicated that the overall configuration of both wild-type and polymorphic CASP8 protein were similar, with negligible deviation at the site of the polymorphism itself. In summary, low penetrance variants in CASP8 gene may alter the susceptibility toward GBC.

CASP8 polymorphisms contribute to cancer susceptibility: evidence from a meta-analysis of 23 publications with 55 individual studies

Several potentially functional polymorphisms of CASP8 encoding an apoptotic enzyme, caspase 8, have been implicated in cancer risk, but individually published studies showed inconclusive results. We performed a meta-analysis of 23 publications with a total of 55 174 cancer cases and 59 336 controls from 55 individual studies. We summarized the data on the associations between three studied CASP8 polymorphisms (G>C D302H, -652 6N del and Ex14-271A>T) and cancer risk and performed subgroup analysis by ethnicity, cancer type, study design and etiology. We found that D302H CC and CG variant genotypes were associated with significantly reduced overall risk of cancers using conservative random genetic models [homozygote comparison: odds ratios (OR) = 0.79; 95% confidence interval (CI): 0.69-0.92; dominant comparison: OR = 0.93, 95% CI: 0.89-0.98; recessive comparison: OR = 0.81, 95% CI: 0.71-0.93). In further stratified analyses, the reduced cancer risk remained for subgroups of Caucasians, breast or estrogen-related cancers, and hospital- or population-based studies, except for an elevated risk for brain tumors. Similarly, the -652 6N del polymorphism was also associated with significantly reduced overall risk of cancers (homozygote comparison: OR = 0.84, 95% CI: 0.75-0.94; dominant comparison: OR = 0.88, 95% CI: 0.81-0.96; recessive comparison: OR = 0.90, 95% CI: 0.82-0.99) and all subgroups analyzed. However, the Ex14-271A>T polymorphism did not appear to have an effect on cancer risk. These results suggest that CASP8 D302H and -652 6N del polymorphisms are potential biomarkers for cancer risk.

Association of selected polymorphisms of CCND1, p21, and caspase8 with colorectal cancer risk

It has been well elucidated that the signal transduction of cell-cycle control pathway and apoptosis pathway plays an important role in the normal growth and differentiation of organisms. To test the hypothesis that mutants of key genes involved in cell-cycle regulation and apoptosis might contribute to the increased risk of colorectal cancer (CRC), a population-based case-control study was carried out in Jiashan County, Zhejiang Province. The study population was composed of 373 CRC cases and 838 controls. Five genetic variants including CCND1 G870A, p21 codon31 C/A, p21 3'UTR C/T, caspase8 IVS12-19G/A, and caspase8 6n del/ins were genotyped. The associations of the polymorphisms with CRC were estimated by logistical regression model after adjustment for the important covariates. The interactive effect among the five selected genetic polymorphisms on CRC was explored by multifactor dimensionality reduction (MDR) software. The significant association between five single-nucleotide polymorphisms (SNPs) and CRC risk was not observed, respectively. However, caspase8 del/del showed a marginally significant association with the increased risk of rectum cancer [adjusted odds ratio (OR) (95% confidence interval, CI) = 1.92 (0.97-3.79); P = 0.06]. Furthermore, the MDR analysis indicated that the best interactive model for CRC included three factors-CCND1 G870A, caspase8 IVS12-19G/A, and caspase8 6 n del/ins-with 53.44% testing balanced accuracy and 10/10 cross-validation consistency, but the model was no longer significant after the 1000 times permutation test (P = 0.25). Our findings suggest that the selected polymorphisms of p21, CCND1, and caspase8 may not contribute to the risk of colorectal cancer.

Polymorphisms in the CASPASE Genes and Survival in Patients With Early-Stage Non–Small-Cell Lung Cancer

Purpose

This study was conducted to determine the impact of potentially functional polymorphisms in the CASPASE (CASP) genes on the survival of early-stage non–small-cell lung cancer (NSCLC) patients.

Patients and Methods

Four hundred eleven consecutive patients with surgically resected NSCLC were enrolled. Nine potentially functional polymorphisms in the CASP3, CASP7, CASP8, CASP9, and CASP10 genes were investigated. The genotype and haplotype associations with overall survival (OS) and disease-free survival (DFS) were analyzed.

Results

Patients with the rs2227310 GG genotype had a significantly decreased OS and DFS compared with patients with the CC + CG genotype (adjusted hazard ratio [aHR] for OS, 1.67; 95% CI, 1.19 to 2.35; P = .003; aHR for DFS, 1.62; 95% CI, 1.19 to 2.22; P = .002). The rs4645981C>T genotype also had a significant effect on OS and DFS (under a recessive model; aHR for OS, 2.00; 95% CI, 1.04 to 3.85; P = .04; aHR for DFS, 2.76; 95% CI, 1.58 to 4.80; P = .0003). When the rs2227310 and rs4645981 genotypes were combined, patients with one or two bad genotypes had worse OS and DFS compared with those who had zero bad genotypes (aHR for OS, 1.75; 95% CI, 1.25 to 2.45; P = .001; aHR for DFS, 1.66; 95% CI, 1.23 to 2.26; P = .001).

Conclusion

The CASP7 rs2227310 and CASP9 rs4645981 polymorphisms may affect survival in early-stage NSCLC. The analysis of these polymorphisms can help identify patients at high risk for a poor disease outcome.

HLungDB: an integrated database of human lung cancer research

The human lung cancer database (HLungDB) is a database with the integration of the lung cancer-related genes, proteins and miRNAs together with the corresponding clinical information. The main purpose of this platform is to establish a network of lung cancer-related molecules and to facilitate the mechanistic study of lung carcinogenesis. The entries describing the relationships between molecules and human lung cancer in the current release were extracted manually from literatures. Currently, we have collected 2585 genes and 212 miRNA with the experimental evidences involved in the different stages of lung carcinogenesis through text mining. Furthermore, we have incorporated the results from analysis of transcription factor-binding motifs, the promoters and the SNP sites for each gene. Since epigenetic alterations also play an important role in lung carcinogenesis, genes with epigenetic regulation were also included. We hope HLungDB will enrich our knowledge about lung cancer biology and eventually lead to the development of novel therapeutic strategies. HLungDB can be freely accessed at http://www.megabionet.org/bio/hlung.

A six-nucleotide insertion-deletion polymorphism in the CASP8 promoter associated with risk and progression of bladder cancer

PURPOSE

Caspase-8 (CASP8) is a key regulator of apoptosis or programmed cell death, an essential defense mechanism against hyperproliferation and malignancy. We hypothesized that the variants in the CASP8 gene are associated with risk of bladder cancer.

EXPERIMENTAL DESIGN

In a hospital-based case-control study of 365 case patients with newly diagnosed bladder transitional cell carcinoma and 368 cancer-free controls frequency-matched by age and sex, we genotyped the functional -652 6N ins/del polymorphism (rs3834129) in the promoter of CASP8 and assessed its associations with risk of bladder cancer and interaction with tobacco smoking.

RESULTS

A significant decreased risk of bladder cancer was found for the CASP8 -652 6N ins/del (adjusted odds ratio, 0.72; 95% confidence interval, 0.53-0.99) and del/del (odds ratio, 0.37; 95% confidence interval, 0.18-0.77) genotypes. Furthermore, a significant additive interaction between CASP8 polymorphism and tobacco smoking on bladder cancer risk was observed.

CONCLUSIONS

These results suggested that the CASP8 -652 6N ins/del polymorphism is involved in etiology of bladder cancer and thus may be a marker for genetic susceptibility to bladder cancer in Chinese populations. Larger studies are warranted to validate our findings.

Genetic variants and haplotypes of the caspase-8 and caspase-10 genes contribute to susceptibility to cutaneous melanoma

Caspase-8 (CASP8) and caspase-10 (CASP10) play key roles in regulating apoptosis, and their functional polymorphisms may alter apoptosis and cancer risk. However, no reported studies have investigated the association between such polymorphisms and the risk of cutaneous melanoma (CM). In a hospital-based study of 805 non-Hispanic white patients with CM and 835 cancer-free age-, sex-, and ethnicity-matched controls, we genotyped three reported putatively functional polymorphisms of CASP8 and CASP10-CASP8 D302 H (rs1045485:G>C), CASP8 -652 6N del (rs3834129:-/CTTACT), and CASP10 I522L (rs13006529:A>T)-and assessed their associations with risk of CM and interactions with known risk factors for CM. We also calculated the false-positive report probability (FPRP) for significant findings. CASP8 302 H variant genotypes (DH: adjusted odds ratio [OR], 0.70; 95% confidence interval [CI], 0.50-0.98; DH+HH: unadjusted OR, 0.78; 95% CI, 0.62-0.98; FPRP, 0.79) and CASP8 -652 6N del variant genotypes (ins/del: OR, 0.74; 95% CI, 0.57-0.97; ins/del+del/del: OR, 0.76; 95% CI, 0.61-0.95; FPRP, 0.61) were associated with significantly lower CM risk than were the DD and ins/ins genotypes, respectively. However, the CASP10 522L variant genotypes were not associated with significantly altered CM risk. Also, the D-del-I haplotype was associated with a significantly lower CM risk (OR, 0.52; 95% CI, 0.37-0.74; FPRP, 0.04) than was the most common haplotype, D-ins-I. Furthermore, multivariate logistic regression analysis revealed that CASP8 D302 H, CASP8 -652 6N del, and CASP10 I522L were independent risk factors for CM. Therefore, these CASP8 and CASP10 polymorphisms may be biomarkers for susceptibility to CM.

CASP3 polymorphisms and risk of squamous cell carcinoma of the head and neck

PURPOSE

Caspase-3 plays a central role in executing cell apoptosis and thus in carcinogenesis, but little is known about the role of CASP3 variants in susceptibility to SCCHN.

EXPERIMENTAL DESIGN

Genotype and haplotypes of the first intron (rs4647601:G>T and rs4647602:C>A) and 5'-untranslated region (UTR; rs4647603:G>A) of CASP3 (NT_022792.17) were determined for 930 SCCHN patients and 993 cancer-free controls in a U.S. non-Hispanic white population. Odds ratio (OR) and 95% confidence interval (95% CI) were calculated in multivariate logistic regression analysis.

RESULTS

We found that the CASP3 rs4647601:TT variant genotype was associated with an increased risk of SCCHN (adjusted OR, 1.32; 95% CI, 1.00-1.73) compared with the GG genotype. This risk was more evident in the subgroups of younger (< or =56 years) subjects, males, and never smokers with a significant trend for increased risk with increased number of variant T allele (P < 0.05 for all). However, these risks were not found for other two SNPs. Furthermore, individuals with two copies of haplotypes TCG or GCA were found to have a significant increased risk of SCCHN (OR, 1.31; 95% CI, 1.07-1.61) compared with the other haplotypes, and this risk was more evident in less advanced diseases (OR, 1.45; 95% CI, 1.11-1.89) than in the advanced diseases (OR, 1.22; 95% CI, 0.96-1.54).

CONCLUSIONS

These results suggested that genetic variation in CASP3 may contribute to SCCHN risk. Larger studies are needed to confirm our findings.

Caspase polymorphisms and genetic susceptibility to multiple myeloma

Multiple myeloma is a haematological malignency, characterized by clonal expansion of plasma cells. However, little is known about the cause of multiple myeloma. Cancer cells must avoid apoptosis to ensure unregulated tumour formation and growth. The highly conserved caspase cascade is essential to the regulation of the apoptotic pathway. To examine if five single nucleotide polymorphisms (SNPs) in four caspase genes [CASP3 Ex8-280 C > A (rs6948), CASP3 Ex8 + 567 T > C (rs1049216), CASP8 Ex14-271 A > T (rs13113), CASP9 Ex5 + 32 G > A (rs1052576), CASP10 Ex3-171 A > G (rs39001150)] alter multiple myeloma risk, we conducted a population-based case-control study of women (128 cases; 516 controls) in Connecticut. Compared to individuals with the TT genotype of CASP3 Ex8 + 567 T > C, subjects with the CC genotype had a five-fold decreased risk of multiple myeloma (odds ratio (OR)(CC) = 0.2, 95% confidence interval (CI) = 0.0-1.0). Further, individuals with the AG and AA genotypes of CASP9 Ex5 + 32 G > A also experienced a decreased risk of multiple myeloma (OR(AG) = 0.8, 95% CI = 0.5-1.3; OR(AA) = 0.5, 95% CI = 0.3-0.9; p-trend = 0.02). While no previous study has evaluated the association between caspase genes and multiple myeloma, studies have found associations with lung, breast, esophageal, gastric, colorectal and cervical cancers. Our parallel study of non-Hodgkin lymphoma, which utilized the same controls, found strong evidence that caspase genes play a key role in lymphogenesis. The protective associations observed in two key caspase genes suggest that genetic variation in CASP genes may play an important role in the aetiology of multiple myeloma.

Identification of polymorphisms in the XIAP gene and analysis of association with lung cancer risk in a Korean population

The X-linked inhibitor of apoptosis protein (XIAP) is a potent mammalian IAP, and has been shown to play an important role in development and progression of cancer. Polymorphisms in the XIAP gene may influence XIAP production or activity, thereby modulating susceptibility to lung cancer. To test this hypothesis, we first screened for polymorphisms in the XIAP gene by direct sequencing of genomic DNA samples from 27 healthy Korean women and then performed a case-control study to evaluate the association between the polymorphisms and the risk of lung cancer. The XIAP genotypes were determined by polymerase chain reaction amplification and melting curve analysis in 582 lung cancer patients and in 582 healthy control subjects who were frequency-matched for age and sex. We identified 12 single nucleotide polymorphisms (SNPs), one novel SNP [30051C>G (A321G) in exon 3] and the following 11 known SNPs: 192G>C (rs5956578), 262C>T (rs28382699), 318C>T (rs5958318), and 374C>T (rs12687176) in the putative promoter; 26615A>G (rs2355676) in intron 1; 41725A>G (rs5958338) in intron 5; 42009A>C (Q423P, rs5956583) in exon 6; 48162T>C (rs17334739) and 48228C>T (rs28382739) in intron 6; and 48542A>G (rs28382740) and 49333G>T (rs28382742) in 3'-UTR. Four of these 12 SNPs were selected for large-scale genotyping based on their frequencies and haplotype tagging status: 262C>T, 318C>T, 374C>T, and 42009A>C. The four XIAP polymorphisms and their haplotypes exhibited no apparent relationship with the risk of lung cancer. In addition, we observed no evidence of effect modification by age, sex, smoking history, or tumor histology. These results suggest that XIAP polymorphisms do not significantly affect susceptibility to lung cancer in Koreans.