BackgroundBreast cancer is a multifactorial disease which involves number of molecular factors that are critically involved in proliferation of breast cancer cells.MEN1gene that is traditionally known for its germline mutations in neuroendocrine tumors is associated with high risk of developing breast cancer in females with MEN1 syndrome. However, the paradoxical role ofMEN1is reported in sporadic breast cancer cases. The previous studies indicate the functional significance ofMEN1in regulating breast cells proliferation but its relevance in development and progression of breast cancer is still not known. Our study targets to find the role ofMEN1gene aberration and its clinical significance in breast cancer.MethodsBreast tumor and adjacent normal tissue of 142 sporadic breast cancer patients were collected at the time of surgery. The expression analysis ofMEN1mRNA and protein was done through RT-PCR, immunohistochemistry and western blotting. Further to find the genetic and epigenetic alterations, automated sequencing and MS-PCR was performed respectively. Correlation between our findings and clinical parameters was determined using appropriate statistical tests.ResultsMEN1expression was found to be significantly increased in the breast tumor tissue with its predominant nuclear localization. The elevated expression ofMEN1mRNA (63.38% cases) and protein (60.56% cases) exhibited a significant association with ER status of the patients. Most of the cases had unmethylated (53.52%)MEN1promoter region, which can be a key factor responsible for dysregulated expression ofMEN1in breast cancer cases. Our findings also revealed the significant association ofMEN1mRNA overexpression with Age and lymph node status of the patients.ConclusionOur results indicate upregulated expression ofMEN1in sporadic breast cancer patients and it could be critically associated with development and advancement of the disease.