Background and Aim: Breast cancer (BC) is the fifth leading cause of cancer death in the world, and the number of women with this malignancy is increasing as well. So, discovering novel biomarkers are very important in the diagnosis and treatment of BC patients. Long non-coding RNAs are RNA transcripts with more than ۲۰۰ nucleotides in length that play a crucial role in cellular biological processes such as tumor formation and progression of malignancies. Aberrant changes in lncRNAs gene expression are correlated with many cancers. Therefore, they have great potential for use as molecular markers for the recognition and target therapy of many diseases. The MCM۳AP-AS۱ is an Antisense۱ lncRNA that misregulates the gene expression in some malignancies such as hepatocellular carcinoma, papillary thyroid cancer, and several other cancers. The aim of this study is the evaluation of the differences in MCM۳AP-AS۱ gene expression levels in BC tumor compared to the marginal non- tumor BC tissues.Methods: In this study, specimens of the tumor and marginal non-tumor tissues were collected from ۱۰ female patients with BC under the mastectomy surgery. RNA extraction and cDNA synthesis were performed for all samples based on the company's protocol. Then, differences in MCM۳AP-AS۱ gene expression levels were assessed by Quantitative Real-Time PCR method. After obtaining the Ct values for each sample, the ۲-∆Ct was calculated to detect the gene expression levels of MCM۳AP-AS۱ in BC tissues as compared to the marginal non-tumor tissues. Finally, the data were analyzed using the Paired t-test and Independent Samples t-test in SPSS and GraphPad PRISM softwares.Results: Evaluation of
qRT-PCR data demonstrated that the significant increase in MCM۳AP-AS۱ gene expression occurred in tumor tissues of patients with BC as compared to the marginal non-tumor tissues (p-value < ۰.۰۵).Conclusion: Given the significant overexpression of MCM۳AP-AS۱ in breast tumor tissues, this lncRNA could act as an oncogene in BC.