Determination of expression profile of p53 gene in different grades of breast cancer tissues by real time PCR

Background: Pakistan has a high incidence of breast cancer in Asia, where annually 16,232 deaths are reported. There are many exogenous and endogenous risk factors that affect the tumor suppressor genes and oncogenes. The p53 gene is a tumor suppressor gene and it has a role to protect the whole genome from external and internal stresses, which causes damages to the genome.
Objective: The aim of the current study was to investigate the p53 gene expression by using the real-time PCR technique in different grades of breast cancer as compared to the normal tissue.
Methods: Fresh Modified Radical Mastectomy (MRM) samples (grade1-grade3) were collected from different hospitals of the Lahore. The project was approved by an ethical review committee of Jinnah Hospital, Lahore. And before sampling an informed consent was obtained from patients and clinicians. RNA from fresh biopsies was extracted by Qiagen extraction kit and cDNA was formed. Real time PCR performed by using SYBR green master mix (ABI) and the data was evaluated by using Livak method. Statistical analysis was done by using Microsoft Excel.
Results: There was an abnormal gene expression of p53 in all grades of the breast tumors. Non-significant (p>0.05) difference of down and up regulation of p53 in different grades of breast tumor was found. However, as a whole up-regulation was more than down-regulation with significant difference (p<0.0011).
Conclusion: The abnormal expression of p53 shows that there are some genetic and epigenetic factors which are the primal cause of an abnormal gene expression. It is recommended that perform next generation sequencing (NGS) of the gene to find out the mutations causing the abnormal behavior of p53 gene.

Keywords
Breast cancer; up-regulation; down-regulation; real-time PCR; Punjab; Pakistan; p53 gene.