Evaluation of Bax and BCL 2 Genes Polymorphisms in Iraqi Women with Breast Cancer

Abstract

The present study aimed to examine the polymorphism -938C > A of BCL-2 gene and promoter -248G>A in the Bax gene, as well as their relationship with specific clinical-pathological characteristics, in patients with breast cancer. Blood samples were obtained from 70 patients who had been diagnosed with breast cancer and 34 healthy women as the control group. Polymorphic analysis was performed using the polymerase chain reaction-restriction fragment length polymorphism assay. Anthropometric data were assessed. Estrogen receptor (ER), human epidermal growth factor receptor 2 (Her-2), and progesterone receptor (PR) were measured by immunohistochemistry. The data of age and body mass index (BMI) demonstrated no significant variations between the two groups (P>0.05). The results of HER-2 revealed that 42.86% of breast cancer patients reflected positively for Her-2/neu expression, while 24.29% reflected negative results of Her-2/neu. Moreover, the results of ER revealed that 42.86% and 28.57% of subjects were positive and negative ER, respectively; moreover, the missing data was 28.57%. In addition, the results of PR indicated that 35.71% of patients (25/70) were positive for PR, while 28.57% reflected negative results, and the missing results were 35.71%. The genotype and allele frequencies of BCL-2(-938C>A) were not statistically significant in women with breast cancer and the control group (P=0.574, P=0.533) for heterozygous and recessive models, respectively. The genotype of BCL-2(-938C>A) in control and patients in codominant, dominant, recessive, and additive models demonstrated no significant variations of all genotypes in all groups. Genotypes and allele frequencies for Bax (-248G>A) in patients with breast cancer and control indicated that the frequencies of GG, AG, and AA genotypes in cases were 16.67%, 3.33%, and 80 %, while in controls, these values were 3.23 %, 58.06 %, and 3.23 %, respectively. The heterozygous genotype (AG) in the codominant model was OR=36.00 (95% CI: 4.5608 - 284.1608; P=0.0007). In comparison with the wild type (GG), there was a 36-fold increase in the risk of breast cancer. Furthermore, the findings of this study revealed a significant correlation between Bax (-248G>A) polymorphism and breast cancer risk under the dominant and overdominant (OR=6.33; 95% CI: 2.2604 -17.7452; P=0.0004, and OR=40.154; 95% CI: 5.1365 - 313.8949; P=0.0004, respectively. The recessive model revealed that there was a decreased risk of breast cancer (OR= 0.167; 95% CI: 0.0303 to 0.9168; P=0.039). Based on the results, it can be concluded that there were no significant variations in BCL-2 (-938C>A) polymorphism of all genotypes models when breast cancer women are compared with healthy ones. In a similar vein, there was no significant association between the BCL-2 (-938C>A) polymorphism and breast cancer risk under dominant, codominant, or recessive models.

Keywords

• bax gene
• bcl-2 gene
• breast cancer
• 248g>a polymorphism
• -938c > -97h526a polymorphism
• iraq