CASP8 -652 6N del polymorphism contributes to colorectal cancer susceptibility: evidence from a meta-analysis

A meta-analysis of caspase-8 -652 6N del polymorphism and digestive tract cancer risk

Caspase-8 (CASP8) is one key regulator of apoptosis of T lymphocytes and is encoded by the CASP8 gene. It has been reported that the six-nucleotide deletion polymorphism (-652 6N del) of the CASP8 gene had effect on some cancer risk. Few studies explored the association between CASP8 gene polymorphism and digestive tract cancer risk. To evaluate the association between the CASP8 -652 6N del polymorphism and the risk of digestive tract cancer, we conducted this meta-analysis. We found that CASP8-652 6N del polymorphism was associated with a significantly reduced risk of digestive tract cancer in the co-dominant model (del/del vs. ins/ins: OR= 0.82, 95%CI= 0.72-0.95; del/ins vs. ins/ins: OR= 0.92, 95%CI= 0.87-0.97; dominant model (del/ins+ del/del vs. ins/ins: OR= 0.91, 95%CI= 0.87-0.96, recessive model: del/del vs. del/ins+ ins/ins: OR= 0.85, 95%CI= 0.75-0.97). In the stratified analysis by cancer types, we found that all genetic models had protective effect on gastric cancer. Similar results were observed for colorectal cancer under heterozygote comparison and dominant model, but not under homozygote comparison or recessive model. In addition, a significantly decreased risk was found on esophageal cancer for most genetic models, except heterozygote comparison. When stratified by ethnicity and source of control, an evidently decreased risk was identified in the Asian populations and population-based studies. In conclusion, there exists an association between the CASP8 -652 6N del polymorphism and reduced digestive cancer risk, especially among Asians and population-based studies.

CASP8 -652 6N insertion/deletion polymorphism and overall cancer risk: evidence from 49 studies

The CASP8 -652 6N insertion/deletion (I/D) polymorphism reduces expression of caspase 8. We conducted a meta-analysis to clarify the relationship between this polymorphism and cancer risk. Eligible articles were retrieved from PubMed, EMBASE, CNKI, and WANFANG databases through February 2017. A total of 33 articles with 49 studies, including 33,494 cases and 36,397 controls, were analyzed. We found that the CASP8 -652 6N ins/del polymorphism was associated with decreased overall cancer risk in five genetic models [DD vs. II: odds ratio (OR)=0.76, 95% confidence interval (CI)=0.69–0.84, ID vs. II: OR=0.87, 95% CI=0.83–0.92, DD vs. ID/II: OR=0.82, 95% CI=0.75–0.89, ID/DD vs. II: OR=0.85, 95% CI=0.80–0.90, and D vs. I: OR=0.87, 95% CI=0.83–0.91]. Stratified analyses showed that the polymorphism was associated with decreased risk of colorectal, breast, esophageal, renal cell, lung, cervical, bladder, gastric, and other cancers. Overall cancer risk was reduced in Asian and Caucasian patients, both hospital- and population-based studies, and both high and low quality studies. Our results highlight the role of the CASP8 -652 6N ins/del polymorphism in decreasing cancer risk. Further studies with large-cohort populations, especially for specific cancer types and ethnic groups, are needed to confirm our findings.

MiR-376a promotion of proliferation and metastases in ovarian cancer: Potential role as a biomarker

AIMS

Ovarian cancer is the fifth most deadly cancer in women, and is usually diagnosed too late. Exploring specific and sensitive biomarkers will be helpful to early detection and will improve the survival rates of ovarian cancer patients.

MAIN METHODS

Realtime PCR was used to detect the expression of miR-376a. Wound healing and transwell assays were used to examined the migration and invasion abilities of ovarian cancer cells. Tumor xenograft experiments were employed to test the in vivo malignancy of ovarian cancer cells. Western Blotting and luciferase report assays were conducted for the target genes analysis.

KEY FINDINGS

Using a cohort of 32 cases of ovarian cancer and 10 cases of healthy control samples, we found that miR-376 expression is increased in ovarian cancer tissues. The serum level of miR-376a is significantly higher in ovarian cancer patients and is associated with the clinical stages of ovarian cancer. Over expression of miR-376a stimulated the proliferation, migration, and invasion of ovarian cancer cells, while inhibition of miR-376a expression blocked the proliferation, migration, and invasion. Data from nude mice further demonstrated the stimulatory role of miR-376a in ovarian cancer progression. Mechanically, miR-376a played its role by targeting KLF15 and Caspase-8.

SIGNIFICANCE

Our findings enrich the knowledge of miR-376a in ovarian cancer formation and progression, providing a possibility of using miR-376a as a diagnostic and prognostic biomarker for ovarian cancer.

Prognostic relevance of caspase 8 -652 6N InsDel and Asp302His polymorphisms for breast cancer

Background

The minor allele of two caspase 8 polymorphisms, namely CASP8 -652 6N InsDel (rs3834129) and CASP8 Asp302His (rs1045485), were repeatedly associated with reduced breast cancer susceptibility. Contrarily, the presence of the -652 6N Del or the CASP8 302His variant was reported to be an unfavorable prognostic factor in colorectal cancer or neuroblastoma. However, prognostic relevance of these genetic variants for breast cancer is completely unknown and is therefore adressed by the current study.

Methods

Genotyping was performed by pyrosequencing. Caspase 8 mRNA expression was quantified by comparative RT-qPCR.

Results

We observed an allele-dose dependent association between CASP8 -652 6N InsDel and caspase 8 mRNA expression in breast cancer tissue, with homozygous deletion carriers showing lowest relative caspase 8 expression (p = 0.0131). Intriguingly, the presence of the -652 6N Del or the 302His variant was shown to be a negative prognostic factor for breast cancer in terms of an allele-dose dependent influence on overall survival (OS, p = 0.0018, p = 0.0150, respectively). Moreover, both polymorphisms were independent predictors of OS after adjusting for co-variats (p = 0.007, p = 0.037, respectively). Prognostic relevance of both polymorphisms were confirmed to be independent from each other and combined analysis of diplotypes revealed an additive influence upon OS (p = 0.0002).

Conclusion

This is the first report, showing negative and independent prognostic impact of the CASP8 -652 6N Del and the 302His variant for breast cancer. Our data provide rationale to further validate clinical utility of these polymorphisms for breast cancer and to extend this investigation to a broad scope of other malignancies.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-2662-x) contains supplementary material, which is available to authorized users.

EGF +61A/G polymorphism contributes to increased gastric cancer risk: evidence from a meta-analysis

Background

Epidermal growth factor (EGF) plays a pivotal role in cell proliferation, differentiation, and tumorigenesis of epithelial tissues. Variation of the EGF +61A/G (rs4444903) can lead to an alteration in EGF production and/or activity, which may result in individual susceptibility to gastric cancer. Studies investigating the association between EGF +61A/G polymorphism and gastric cancer risk produced inconsistent results. The aim of this study was to quantitatively summarize the evidence for such an association.

Methods

Eligible studies on the association between EGF +61A/G polymorphism and gastric cancer risk were identified by search of electronic databases including PubMed, EMBASE, Cochrane Library, and Chinese Biomedical Literature database (CBM). Data were extracted by two independent authors and pooled odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of the association. Metaregression and subgroup analyses were performed to identify the source of heterogeneity.

Results

Finally, six case–control studies with 1547 gastric cancer cases and 2762 controls were eventually identified. Overall, significant increased gastric cancer risk was found when all studies were pooled in the meta-analysis (GG vs. AA: OR = 1.438, 95% CI 1.021–2.025, P = 0.038; GG + AG vs. AA: OR = 1.256, 95% CI 1.025–1.539, P = 0.028; GG vs. AG + AA: OR = 1.265, 95% CI 1.002–1.596, P = 0.048). In subgroup analysis by ethnicity, source of control, study quality, and HWE in controls, significant increased gastric cancer risk was observed in Asians, population-based studies, high quality studies, and studies consistent with HWE. In subgroup analysis according to tumor location, and histological type, significant association was observed in all subgroups.

Conclusions

This meta-analysis suggested that the EGF +61A/G polymorphism contributes to increased gastric cancer risk, especially in Asian populations. Further well-designed studies based on large sample size in diverse populations are needed to confirm this association.