A Review of the Function of Circulating Cell Free miRNAs as Promising Biomarkers in Cancer Diagnosis, Treatment, and Metastasis

Cell Free miRNAs are small, non-coding molecules that can be secreted into the bloodstream in very stable forms. These types of miRNAs, like intracellular miRNAs, participate in the control of many biological processes and are expressed in both natural and pathological conditions. Quantitative and qualitative changes in expression of circulating miRNAs are associated with the onset and progression of cancer, but can be easily detected by some molecular biology methods. The most common methods for diagnosis, prognosis, and treatment of most cancers are aggressive, so finding accurate and non-invasive methods for early diagnosis, monitoring and control of cancer are essential. The circulating miRNAs affect not only cells near the site of secretion but also distant tissues, so, they can lead to cancer progression. Herein, we examined studies based on the identification of circulating miRNAs as non-invasive diagnostic biomarkers, prognostic, and of course important for the treatment of various types of cancers.