Abstract 1054: Reciprocal circRNA-miRNA expression axes indicative of early tumor initiation in breast

Abstract Cancer prevention and early detection are the most effective tools for cancer control. In this study, we adopt a novel approach of identifying a network of proteins/mRNA-circRNA-miRNA axes. We hypothesize that mutation of oncogenes or tumor suppressor genes during pre-oncogenic stage result in aligned change in levels of circular RNAs-derived genes, as well as, reciprocally, in corresponding sponged miRNAs. These epigenetic risk predictive proteins/mRNA-circRNA-miRNA axes serve as potential tool for early detection of changes leading to breast cancer (BC) and can be further used as non-invasive screening biomarkers of patients’ blood in populations susceptible to cancer. BC patients in GDC Data Portal, TCGA-BRCA project are selected based on several criteria such as their age at diagnosis (20-50 years old), early clinical stage of cancer (stage I) and disease type (ductal and lobular neoplasms). Differentially expressed genes are acquired from mRNA sequencing data by comparing Stage I Breast cancer versus normal primary tissues using R Studio. Then, mRNAs whose expression is aligned with the differentially expressed circRNAs and their host genes acquired from Gene Expression Omnibus (GEO) (GSE182471, Triple Negative Breast cancer tissues versus normal tissues) are selected. Differentially expressed miRNAs, in reciprocal expression with circRNAs, are defined using miRNA sequencing data of the same previously chosen TCGA BRCA patients. Selected miRNAs are hypothesized to be sponged with high confidence by selected circRNAs based on a context percentile binding score in CircInteractome. Using KM Plotter, the survival analysis of corresponding miRNAs in grade I BC patients is examined. The predicted miRNA expression was correlated with lower survival rates among stage I BC patients in KM Plotter. MiRNA-enrichment analysis is used to further validate the involvement of selected miRNAs in early tumorigenic events through exploring in which molecular pathways their downstream genes are enriched. We have constructed more than 20 potential proteins/mRNA-circRNA-miRNA axes for non-invasive screening of patients’ body fluid (i.e. Blood) in populations susceptible to BC using RNA and miRNA sequencing data available in online databases and further validate the proposed axes using in-silico tools. The described axes, once validated in clinical samples could provide a potential tool for early-stage BC prediction and prevention. Citation Format: Nour Abbas Maatouk, Sarah Hussein Marei, Abdallah Bilal Kurdi, Nadim Shady Hamade, Rihab Raif Nasr, Rabih Shakib Talhouk. Reciprocal circRNA-miRNA expression axes indicative of early tumor initiation in breast [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1054.