The BCL-2 promoter (-938C>A) polymorphism does not predict clinical outcome in chronic lymphocytic leukemia

Correlation between Bax gene polymorphisms and esophagus cancer

The present study investigated the association between the G(-248)A single nucleotide polymorphism (SNP) in the promoter region of B-cell lymphoma 2 (Bcl-2) associated X protein (Bax), which is a pro-apoptosis gene and the clinicopathological parameters and prognosis of patients with esophagus cancer. Three genotypes (AA, AG and GG) of Bax G(-248)A SNP were detected in 75 patients with esophageal squamous cell carcinoma (ESCC) via polymerase chain reaction-restricted fragment length polymorphism (PCR-RFLP). The expression of Bax in tumor tissues from 75 patients with ESCC and 30 para-carcinoma normal tissues were detected via immunohistochemistry. The association between the Bax protein expression and the Bax gene polymorphism was analyzed via the χ2 test. The clinical data of patients was collected and the association between Bax gene polymorphism and the pathological parameters and the prognosis of patients with ESCC was analyzed. The PCR-RFLP results revealed that the number of cases and the distribution frequencies of GG, AG and AA genotypes of Bax polymorphism in patients with ESCC were 50 (66.67%), 16 (21.33%) and 9 (12%), respectively. The immunohistochemical results revealed that the positive expression rate of Bax in ESSC tissues was 42.67%. Bax protein expression was associated with the Bax gene polymorphism, which was associated with outer membrane infiltration, differentiation degree, lymphatic metastasis and the clinical staging of patients. The overall 5-year survival rate of patients was 38.6% (29/75). The survival analyses revealed that the prognosis of patients with AG+AA genotypes was favorable, while that of patients with GG genotype was poor. Bax gene polymorphism was associated with Bax gene expression, tumor staging and lymphatic metastasis in patients with ESCC, which is an influencing factor for the overall survival rate and may be used as a reference index for the prognosis evaluation of patients with ESCC.

Role of Bcl-2 -938 C>A polymorphism in susceptibility and prognosis of cancer: a meta-analysis

The association between B-cell lymphoma 2 (Bcl-2) polymorphism and cancer is under debate and remains elusive. This meta-analysis was performed to evaluate the relationships of Bcl-2 -938 C>A polymorphism (rs2279115) with susceptibility and prognosis of cancer. Odds ratios (ORs) were used to measure the association between Bcl-2 polymorphisms and cancer risk. Hazard ratios (HRs) were used to measure the association between Bcl-2 polymorphisms and cancer prognosis. On the basis of 26 studies about Bcl-2 -938C>A polymorphism and cancer, we found Bcl-2 -938 C>A polymorphism was significantly associated with increased cancer risk in dominant model (OR = 1.12, 95%CI: 1.00-1.25, P = 0.04), recessive model (OR = 1.38, 95%CI: 1.11-1.71, P = 0.004), allelic model (OR = 1.15, 95%CI: 1.04-1.28, P = 0.007) and homozygote comparison(OR = 1.44, 95%CI: 1.11-1.87, P = 0.006). Furthermore, Bcl-2 -938 C>A polymorphism was significantly associated with increased cancer risk in Asians but not in Caucasians. Moreover, Bcl-2 -938 C>A polymorphism was not significantly associated with the prognosis of cancer (AA vs CA: OR = 0.99, 95%CI: 0.77-1.27, P = 0.93; AA vs CC: OR = 0.92, 95%CI: 0.65-1.30, P = 0.63; AC vs CC: OR = 0.94, 95%CI: 0.80-1.11, P = 0.48; CC vs AA+CA: OR = 1.21, 95%CI: 0.69-2.13, P = 0.50; AA vs CC+CA: OR = 0.99, 95%CI: 0.48-2.04, P = 0.97). Studies with larger samples and gene-environment interactions are needed to validate our findings.

Role of Caspase 8, Caspase 9 and Bcl-2 polymorphisms in papillary thyroid carcinoma risk in Han Chinese population

Dysregulation of apoptosis plays a key role in carcinogenesis. This study was designed to investigate the association of apoptosis-related gene Caspase 8, Caspase 9 and Bcl-2 polymorphisms with papillary thyroid carcinoma (PTC) susceptibility. We undertook a case-control study of 118 patients and 213 controls to investigate the association between Caspase 8 (-652 6 N ins/del), Caspase 9 (-1263 A>G) and Bcl-2 (-938 C>A) polymorphisms and PTC susceptibility by polymerase chain reaction restriction-fragment length polymorphism and DNA sequencing methods. We further analyzed the distribution of genotype frequency, as well as the association of genotype with clinicopathological characteristics. Overall, no statistically significant association was observed in Caspase 8 (-652 6 N ins/del). Nevertheless, Caspase 9 -1263 GG genotype was at increased risk of PTC (P=0.045; odds ratio (OR)=1.12). Furthermore, GG genotype thyroid cancers were significantly more common in older patients than AA or AG genotypes PTC and in cases of advanced pathological stages. However, Bcl-2 -938 AA genotype demonstrated a protective effect in PTCs (P=0.004; OR=0.35). Polymorphism in Caspase 9 (-1263 A>G) was observed to be associated with susceptibility of PTC. However, Bcl-2 (-938 C>A) polymorphism indicated to play a protective role in susceptibility to PTC. Nevertheless, further investigation with a larger sample size is needed to support our results.

BCL-2 (-938C > A) polymorphism is associated with breast cancer susceptibility

Background

BCL-2 (B-cell leukemia/lymphoma 2) gene has been demonstrated to be associated with breast cancer development and a single nucleotide polymorphism (SNP; -938C > A) has been identified recently. To investigate whether this polymorphism functions as a modifier of breast cancer development, we analyzed the distribution of genotype frequency, as well as the association of genotype with clinicopathological characteristics. Furthermore, we also studied the effects of this SNP on Bcl-2 expression in vitro.

Methods

We genotyped the BCL-2 (-938C > A) in 114 patients and 107 controls, and analyzed the estrogen receptor (ER), progestogen receptor (PR), C-erbB2 and Ki67 status with immunohistochemistry (IHC). Different Bcl-2 protein levels in breast cancer cell lines were determined using western blot. Logistic regression model was applied in statistical analysis.

Results

We found that homozygous AA genotype was associated with an increased risk (AA vs AC+CC) by 2.37-fold for breast cancer development and significant association was observed between nodal status and different genotypes of BCL-2 (-938C > A) (p = 0.014). AA genotype was more likely to develop into lobular breast cancer (p = 0.036). The result of western blot analysis indicated that allele A was associated with the lower level of Bcl-2 expression in breast cancer cell lines.

Conclusions

AA genotype of BCL-2 (-938C > A) is associated with susceptibility of breast cancer, and this genotype is only associated with the nodal status and pathological diagnosis of breast cancer. The polymorphism has an effect on Bcl-2 expression but needs further investigation.

BCL2-938C>A polymorphism and disease progression in chronic lymphocytic leukemia

A number of single nucleotide polymorphisms (SNP) have been implicated to impact upon the disease course of chronic lymphocytic leukemia (CLL). However, few of these association studies could be confirmed in independent studies in the past. Recently, three independent studies did not confirm the prognostic impact of a new functional SNP in the BCL2 gene (-938C>A) described by Nückel et al. For this reason we genotyped an independent group of patients with CLL (n = 271) with mature follow up and detailed analysis of molecular genetics. The genotype distribution of this BCL2 polymorphism did not differ from that described in the original work. However, genotypes were not associated with time to first treatment (TFT) and overall survival (OS) in univariate or multivariate analysis in the current cohort. Comparing the characteristics of the two study cohorts in more detail we found differences between the two cohorts demonstrating a potentially more aggressive second study cohort. However, TFT and OS in patients with CLL according to Binet A did not differ significantly depending on the genotype. Our findings underscore the need for optimally matched patient cohorts in replication studies. The study re-emphasizes the need for large cohorts and validation in independent data sets before firm conclusions can be made about genotype-phenotype associations.