Table 1.

List of the studied miRNAs and their functions.

MicroRNAs	Biological Activity	Reference
142	targets ESR1, reduces cell viability, induces apoptosis and decreases colony formation	[72]
203a	is overexpressed in breast cancer and can influence ERα signalling by targeting ADCY5, IGF1, etc.	[73]
219b	downregulates ERα	[74]
520a	targets NF-κB and TGF-β signalling pathways; targets ESR1, inhibits CCND1 mRNA and cyclin D1 protein levels	[75,76]
874	targets ESR1, CDK9	[77]
181a	downregulates ERα; induces AKT signalling	[74,78]