hsa-mir-3609: Hsa-mir-3609 is a microRNA (miRNA) that has been implicated in the regulation of tumor proliferation, migration, stemness, and tumor-intrinsic PD-L1 expression in triple-negative breast cancer (TNBC) cells [PMC9659572]. This miRNA is located on chromosome 7 and has been identified as one of the most upregulated miRNAs in TNBC [PMC6541642]. Functional studies have demonstrated that hsa-mir-3609 can induce a significant reduction in CDK1 protein levels, suggesting a role in cell cycle regulation [PMC6541642]. Additionally, hsa-mir-3609 is predicted to have canonical binding sites on the CDK1 mRNA 3’UTR and is associated with an increase in nuclear-encoded miRNAs following ASK treatment [PMC6541642]. In the context of breast cancer, hsa-mir-3609 has been identified as differentially expressed in the blood samples of patients with locally advanced disease compared to healthy controls [PMC9727336], and it may regulate transcriptional levels of various extracellular matrix (ECM)-related genes and transcription factors [PMC4982685]. Moreover, it has been found to be abundant specifically in CD4+ T cells [PMC9031252], suggesting cell-type-specific expression. In prognostic studies, hsa-mir-3609 has been classified as one of three protective RNAs that may be part of an optimum prognostic signature for disease outcome prediction [PMC7541229]. Despite its emerging significance, research on hsa-mir-3609 remains limited compared to other miRNAs [PMC8350636].