Among them, miRNAs involved in the negative regulation of ERs, such as miR-181a-2, when delivered to target cells, could further induce the rearrangement or interdiction of hormonal signaling or the activation of the PI3K/AKT signaling pathway, ultimately reducing the sensitivity of ER+ breast cancer cells to endocrine therapy (133). This evidence concerns the gene AKT1 and breast carcinoma.