MiRNAs have been found to be dysregulated in many types of cancer, acting either as oncogenes or tumor suppressors. Dysregulation of miRNAs can lead to aberrant cell proliferation, evasion of apoptosis, increased invasion and metastasis, and resistance to chemotherapy. For instance, the miR-21 is often upregulated in various cancers and promotes tumor growth by targeting tumor suppressor genes.
