Study of the regulatory promoter polymorphism (-938C>A) of B-cell lymphoma 2 gene in breast cancer patients of Mazandaran province in Northern Iran

CYP1A1 contiguous hypermethylation within a putative CpG block is associated with breast cancer progression: Feasibility to define boundary motives

Having broad specificity for xenobiotics metabolism throughout the body, cytochrome P450 (CYP) isoform 1A1 is of key relevance for carcinogenesis. However, the oncogenic potential of its altered transcription and the underlying mechanism has not been well-established in breast cancer. Direct bisulfite sequencing PCR (BSP) of the CYP1A1 promoter, enriched by 113 CpGs within and flanking the xenobiotic response elements (XREs) 2 to 10, in paired cancerous and normal tissues from 40 breast cancer patients revealed three distinctly methylated patterns; unmethylated (XREs 2 to 6) and completely methylated (XREs 7 and 8) CpGs, in common for the normal and cancerous tissues, and a putative 171bp CpG block (XREs 9 and 10) contiguously hypermethylated in the tumor tissues. Increased transcription of CYP1A1, observed for the cancerous tissues, was correlated with the hypermethylation of given CpG block, besides simultaneously being associated with upregulation of the anti-apoptotic BCL-2. Clinical value of the methylation changes, investigated based on the comparisons between the tissue cohorts of different clinicopathological features, exhibited gradual hypermethylation of the corresponding CpG block following disease progression as well as lymphatic involvement. Hypermethylation of given CpG block may has potential to be used as a biomarker for diagnosis and progression of breast cancer.

Association of genetic polymorphism of BCL-2 (rs2279115) with susceptibility to HCV-related hepatocellular carcinoma

Hepatitis C virus (HCV) infection is the main risk factor for chronic hepatitis (CHC), liver cirrhosis, and hepatocellular carcinoma (HCC). B cell lymphoma-2 (BCL-2) prevents apoptosis, and its overexpression could promote cancer cell survival. The purpose of this study is to evaluate the association of Bcl-2 gene polymorphism (rs2279115) and HCV-related HCC susceptibility. Two hundred and seventy individuals included in this case-control were divided into three groups. Group I: It included 90 apparently healthy subjects as control. Group II: It includes 90 patients with chronic HCV hepatitis. Group III: It includes 90 patients with HCC with positive HCV. Bcl-2 gene polymorphism (rs2279115) C > A genotypes by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). There are significantly higher incidence of CA and AA genotypes in HCV patients with HCC compared with those without HCC (OR 2.3, %CI (1.2-4.6), P = 0.01 and OR 5.7, %CI (2.4-13.8), respectively) and compared with control group (OR 2.9, %CI (1.5-5.8), P = 0.002 and OR 7.1, %CI (2.9-17.4), P < 0.001, respectively), while no significant difference between the control and HCV patients without HCC groups (OR 1.2, %CI (0. 7-2.4), P = 0.48, for CA, and OR 1.2, %CI (0.4-3.3), P = 0.67, for AA).The frequency of A allele was highly significantly overrepresented in the HCC group in comparison to HCV group (53.3% versus 30.6%, P < 0.001) and control group (53.3% versus 27.2%, P < 0.001) but no significant difference (p = 0.49) between control group and HCV patients. This study demonstrated that Bcl-2 gene polymorphism (rs2279115) was associated with increased susceptibility to HCV-related HCC.

BAX -248 G>A and BCL2 -938 C>A Variant Lowers the Survival in Patients with Nasopharyngeal Carcinoma and Could be Associated with Tissue-Specific Malignancies: A Multi-Method Approach

Background:

The association of BAX -248 G>A and BCL2 -938 C>A with different cancers created conflicts. We studied the correlation and the effect of these polymorphisms in patients with Nasopharyngeal Carcinoma (NPC).

Methods:

PCR-RFLP and Sanger sequencing were used to detect polymorphisms. Statistical analysis including forest plot and Kaplan-Meier Log-rank test was conducted to investigate the association and effect of these SNPs on the NPC patients’ survival. The computational study was performed to investigate the possible regulatory role between these polymorphisms and the poor survival of NPC patients. Meta-analysis was executed to check the tissue-specific association of these polymorphisms in the context of global cancer prognosis.

Results:

We observed an increased and significant association of BAX -248 G>A [GA:OR=5.29, 95%CI=1.67,16.67, P=0.004; GA+AA:OR=5.71, 95%CI=1.82,17.90, P =0.002; A:OR=5.33, 95%CI=1.76,16.13, P=0.003], and BCL2 -938 C>A [CA:OR=2.26, 95%CI=1.03,4.96, P=0.04; AA:OR=3.56, 95%CI=0.97,13.05, P=0.05; CA+AA:OR=3.10, 95%CI=1.51,6.35, P=0.002; A:OR=2.90, 95% CI=1.59,5.29, P=0.0005] with the risk of NPC. Also, these SNPs were strongly correlated with poor survival in NPC patients (lower estimated survival mean, lower estimated proportion surviving at 5 years with p<0.05). The computational study showed that these SNPs altered the binding affinity of transcription factors HIF1, SP1, PAX3, PAX9 and CREB towards promoter (Lower p indicates strong affinity). The meta-analysis revealed the tissue-specific association of these polymorphisms. BAX -248 G>A showed a significant correlation with carcinomas [A vs G:OR=1.60, 95%CI=1.09,2.34, P=0.01; AA vs GG:OR=2.61, 95%CI=1.68,4.06, P<0.001; AA+GA vs GG:OR=1.53,95%CI=1.04,2.25, P=0.02); AA vs GG+GA:OR=2.53, 95%CI=1.65,3.87, P<0.001], and BCL2 -938 C>A with other malignancies [A vs C:OR=1.45, 95%CI=1.26,1.66, P<0.001; AA vs CC:OR=2.07, 95%CI: 1.15,3.72, P=0.01; AA+CA vs CC:OR=1.42, 95%CI=1.18,1.72, P<0.001; AA vs CC+CA:OR=1.89, 95%CI=1.02,3.50, P=0.04].

Conclusions:

BAX -248 G>A and BCL2 -938 C>A was associated with poor survival in NPC patients. It may increase cancer susceptibility through transcriptional regulation. Moreover, these SNPs’ effects could be tissue-specific.

Association between Ki-67 expression and clinicopathological features in prognosis of breast cancer: A retrospective cohort study

Background:

Breast cancer is the most common diagnosed female cancer. Breast cancer is also the leading cause of cancer death in females accounting for 13.7% of female cancer-related mortality globally. Variable known prognostic factors such as histological tumor type, tumor size, nodal status, grade, age, and estrogen receptor (ER) status and the proliferation marker – Ki-67 influence the type of treatment decision. The purpose of this present study is to investigate the association between Ki-67 expression with several clinicopathological variables and patients’ outcome.

Materials and Methods:

This is a retrospective cohort study from September 2008 to March 2017; 165 newly diagnosed breast cancer patients were enrolled in the study. Ki67 levels were measured using immunohistochemistry and compared with clinicopathological variables. The relation of Ki67 expression with disease-free survival (DFS) and overall survival (OS) was also analyzed.

Results:

The result of this study revealed that age, tumor size, menopausal status, and human epidermal growth factor receptor 2 (HER2) status had no effect on the patients’ outcome. Patients with ER-positive, progesterone receptor (PR)-positive, and HER2-negative tumors expressed a higher rate of Ki-67 (>10%) than patients with ER-negative, PR-negative, and HER2-positive tumors, respectively. However, we found that Ki-67 levels were not significantly increased statistically with ER, PR, and HER2 statuses. There was a statistically significant correlation between Ki-67 expression and with higher stages of the disease. Multivariate analysis showed that Ki-67 expression could not to be an independent prognostic factor for 5-year OS and DFS. Furthermore, p53 status was only prognostic factor for 5-year OS whereas higher stages of disease and p53 status were prognostic factors for 5-year DFS.

Conclusion:

Ki67 could not be an independent variable for prediction of breast cancer outcome.