Evaluation of the DAPK gene expression level in peripheral blood lymphocytes of patients with breast cancer

Background: The main causes and difficulties of cancer are the imbalance between cell growth and cell death. This event is the results of changes in the expression level of genes related to these mechanisms. Among genes including in this case, death-associated protein kinase (DAPK) can be mentioned. Studies have shown that the expression of genes is influenced by the methylation of promoter regions. The purpose of this research was to evaluate the expression of the mentioned gene and the effect of methylation on the expression of this gene and its relationship with developing breast cancer in women. Methods: Eighty patients with breast cancer and 80 healthy individuals participated in this case-control study which has been referred to Shahid Faghihi and Namazi hospitals, Shiraz city, from August 2014 to March 2017. This study was carried out at the Genetic Research Center of Islamic Azad University, Kazerun Branch, Iran. Peripheral blood lymphocytes were lysed and the mRNAs were extracted using the InViSorb™ RNA preparation kit II (Cat#1062100300, Invitek GmbH, Berlin, Germany) and cleaned up with Qiagen RNeasy spin columns. The first-strand cDNA was synthesized affording to the high capacity cDNA reverse transcription kit procedure. For DAPK gene expression, (Thermo Fisher Scientific, Waltham, MA, USA) PCR technique combines the quantitative performance of SYBR® Green-based real-time PCR, used. This technique is gainful, easy-to-use, and emphases only on the genes that you want. We designated 18S-rRNA gene, as our house-keeping gene. For determine of methylation, methylation-specific polymerase chain reaction (MS-PCR) method was used.  Results: The achieved results from this research show that the levels of DAPK gene expression have a significant difference. The rate of expression in patients was significantly reduced compared with the control group (P=0.0156). Also, the relationship between expression of DAPK factor and lymph node involvement was investigated. The results show the relationship between the factors studied. On the other hand, there was no significant relationship between the expression level of this gene and its promoter methylation (P=0.13). Conclusion: This research shows that reduction in the rate of DAPK gene expression plays an effective role in the patients with breast cancer