MicroRNAs (miRNAs) are attractive, short, non-coding RNAs widely studied for their fundamental roles in
tissue homeostasis, cell proliferation, and dysregulation in cancer. A vast majority of investigations and technical improvements
have focused on miRNAs' tumor-specific expression patterns, which provide novel molecular biomarkers for
cancer detection and targeted therapies. In this review, we focus on recent achievements in biomarker validation and potential
for cancer treatment, with special trend in non-invasive strategies to evaluate miRNAs, especially for diagnostic
and prognostic applications. We further include a large compilation of PubMed data regarding microRNAs reported as diagnostic
or prognostic cancer biomarkers in at least three studies.