Investigation of p53 and p27 expressions in the N-nitroso-N-methylureainduced breast cancer in female Wistar Albino rats

Introduction: N-nitroso-N-methylurea (NMU) is a carcinogen from nitrosamines family, which has been used to induce breast cancer in rodents. This model of breast cancer is very similar to the estrogen dependent breast cancer in human. As a continuation of our recent works, in the present study, the expressions of both p53 and p27 were investigated in NMU-induced breast cancer in Wistar Albino rats. Methods: Breast cancer was induced by intraperitoneal injection of NMU in Wistar Albino rats, while, normal saline was injected in the control group. After the tumors were formed and reached a proper size, the rats in both groups were sacrificed under anesthesia and samples were obtained from mammary tumors as well as normal breast tissue. Expressions of p53 and p27 genes were investigated by reverse-transcription polymerase chain reaction (RT- PCR). Results: NMU injection induced breast cancer in rats. RT-PCR data showed that p53 expression was increased (p>0.05), while p27 expression was decreased in rat mammary tumors compared with the normal tissue of normal rats (p>0.05). This study is being continued to confirm the results, but these findings are compatible with our previous data about cyclin D1 and p21 expressions in tumor tissue. Conclusion: The results indicate opposite changes in the expression of p53 and p27 in cancerous breast tissue in comparison with the normal breast tissue.