Exploring the Regulatory Roles of miR-21, miR-15, and miR-let-7 in ABC Transporter-Mediated Chemoresistance: Implications for Breast Cancer Etiology and Treatment.

Breast cancer, a prevalent and aggressive malignancy among females worldwide, poses a significant challenge due to resistance to chemotherapy and tyrosine kinase inhibitors. In breast cancer, ABC transporters play a pivotal role by contributing to chemoresistance and drug efflux, a phenomenon observed also in various cancers. This study aims to elucidate the role of oncomiRs miR-15, miR-21, and miR-let-7 in breast cancer etiology and their impact on chemotherapy-resistant oncogenes ABCA1, ABCB1, and ABCC1. Blood samples from female breast cancer patients were analyzed to assess the expression levels of miRNAs and oncogenes by qPCR. Significantly, miR-21 exhibited a positive correlation with ABCA1 in newly diagnosed patients, while miR-15 and miR-let-7 displayed a positive correlation with ABCA1 in the metastasis group. Additionally, miR-let-7 demonstrated a negative correlation with ABCC1 in newly diagnosed patients. This study's findings provide valuable insights into the cancer etiology of these miRNAs and their interactions with ABCA1, ABCB1, and ABCC1. Targeting these interactions holds promise for mitigating drug efflux and chemoresistance in breast cancer, potentially enhancing current treatments and improving patient outcomes.