Biomarkers are biomolecules used to identify or predict the presence of a specific disease or condition. They play an important role in early diagnosis and may be crucial for treatment.
MicroRNAs (
miRNAs), a group of small non-coding RNAs, are more and more regarded as promising
biomarkers for several reasons. Dysregulation of
miRNAs has been linked with development of several diseases, including many different types of
cancer, and abnormal levels can be present in early stages of
tumor development. Because
miRNAs are stable molecules secreted and freely circulating in blood and urine, they can be sampled with little or no invasion. Here, we present an overview of the current literature, focusing on the types of
cancers for which dysregulation of miR-665 has been associated with
disease progression, recurrence, and/or prognosis. It needs to be emphasized that the role of miR-665 sometimes seems ambiguous, in the sense that it can be upregulated in one
cancer type and downregulated in another and can even change during the progression of the same
cancer. Caution is thus needed before using miR-665 as a
biomarker, and extrapolation between different
cancer types is not advisable. Moreover, more detailed understanding of the different roles of miR-665 will help in determining its potential as a diagnostic and prognostic
biomarker.