Polymorphic variations in apoptotic genes and cancer predisposition

The correlation between XIAP gene polymorphisms and esophageal squamous cell carcinoma susceptibility and prognosis in a Chinese population

OBJECTIVE

This study aims to explore the correlation between X-linked inhibitor of apoptosis protein (XIAP) gene polymorphisms (rs8371 and rs9856) with the susceptibility and prognosis of esophageal squamous cell carcinoma (ESCC), providing a potential treatment for ESCC.

METHOD

A total of 170 ESCC patients (case group) and 191 healthy people (control group) were enrolled in our study. Genotyping was conducted on the basis of the ligase detection reaction (LDR). The expressions of XIAP polymorphisms were detected. The patients were followed up every three months until death or the last follow-up day. The overall survival (OS) and progression free survival (PFS) were recorded by Kaplan-Meier survival curve, and the relationship between XIAP gene polymorphism and risk and prognosis of ESCC was assessed by Cox multivariate analysis.

RESULT

TT+CT genotype and T allele frequencies of XIAP rs8371 and rs9856 in the case group were significantly lower compared to those of the control group (all P<0.05), suggesting that TT+CT genotype of XIAP rs8371 and rs9856 was associated with ESCC susceptibility. XIAP rs8371 and rs9856 polymorphisms were associated with tumor node metastasis (TNM) staging, depth of invasion and lymph node metastasis. The OS and PFS of TT+CT genotype carriers of rs8371 were longer than those of CC genotype carriers. Smoking, alcohol, TNM staging, depth of invasion, and lymph node metastasis were significantly associated with the OS and PFS in ESCC patients. Higher TNM staging, depth of invasion, and presence of lymph node metastasis were independent risk factors, while XIAP rs8371 was an independent protective factor for the prognosis of ESCC patients.

CONCLUSION

The present study demonstrates that XIAP rs8371 and rs9856 are associated with susceptibility to ESCC, and rs8371 polymorphisms might serve as an indicator for improved clinical efficacy and prognosis of ESCC patients.

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.

Coding polymorphisms in Casp5, Casp8 and DR4 genes may play a role in predisposition to lung cancer

Apoptosis plays a role in the elimination of DNA-damaged cells thus protecting the host from cancer development. Some data indicate that normal variations within the sequence of apoptotic genes may lead to suboptimal apoptotic capacity and therefore increased cancer risk. We tested 19 coding apoptotic gene SNPs in 2-stage molecular epidemiological study. For the preliminary sorting of SNP candidates, we employed a "comparison of extremes" approach, where 111 patients with highly pronounced LC susceptibility (non-smokers or young-onset light smokers) were analyzed against 110 subjects with the evidence for LC tolerance (elderly tumor-free heavy smokers). Three genotypes demonstrated possible association with LC risk (Leu/Leu-homozygotes for Casp5 Val318Leu versus other genotypes: OR=2.47 (95% CI: 1.07-5.69), p=0.03; His-carriers for Casp8 His302Asp: OR=2.26 (95% CI: 1.18-4.31), p=0.02; Arg-carriers for DR4 Lys441Arg: OR=1.89 (95% CI: 1.05-3.40), p=0.03), and therefore were selected for the validation. The extended study included 2 case-control series, namely subjects from Russia (351 LC cases and 538 controls) and Moldova (296 LC cases and 295 controls). Interestingly, all three candidate genotypes consistently demonstrated OR above 1 both in Russian and in Moldovian groups. Although the combined Mantel-Haenszel analysis yet failed to reach statistical significance (OR=1.22 (95% CI: 0.90-1.65), p=0.21; OR=1.17 (95% CI: 0.92-1.50), p=0.21; OR=1.19 (95% CI: 0.95-1.51), p=0.14, respectively), the obtained data indicate that Casp5, Casp8 and DR4 gene polymorphisms may deserve consideration in large-scale case-control studies of LC risk modifiers.

Polymorphisms in the Caspase7 gene and the risk of lung cancer

BACKGROUND

Caspase7 (CASP7) is an executioner CASP that conducted a coordinated program of proteolysis that results in the destruction of critical cell structures, and it plays an important role in the development and progression of cancer. The purpose of this study is to comprehensively evaluate potential functional polymorphisms in the CASP7 gene in relation to the risk of lung cancer.

METHODS

We first captured seven single nucleotide polymorphisms (SNPs) in the regulating region, exons and exon-intron boundaries of the CASP7 gene using public database and then determined their frequencies in 27 healthy Korean individuals. Next, we examined four SNPs (rs12415607g.C>A; rs11593766g.T>G; rs2227310g.C>G; and rs10787498g.T>C) in a case-control study that consisted of 720 lung cancer patients and 720 healthy controls.

RESULTS

Of the four SNPs studied in the case-control study, only the distribution of the rs2227310g.C>G genotypes differed significantly between the cases and controls (P=0.03). The rs2227310 GG genotype was associated with a significantly increased risk of lung cancer when compared with the rs2227310 CC genotype [adjusted odds ratio (OR)=1.42, 95% confidence interval (CI)=1.05-1.93, P=0.02] and with the combined rs2227310 CC and CG genotype (adjusted OR=1.38, 95% CI=1.05-1.81, P=0.02). Consistent with the results of genotyping analysis, the ATGT haplotype (rs12415607A/rs11593766T/rs2227310G/rs10787498T) was associated with a significantly increased risk of lung cancer when compared to other haplotypes (adjusted OR=1.21, 95% CI=1.04-1.42, P=0.02).

CONCLUSION

These results suggest that the CASP7 polymorphisms contribute to the genetic susceptibility to lung cancer.

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.