What is microRNA and why does it matter for cancer?
MicroRNAs (miRNAs) are small, non-coding RNA molecules approximately 22 nucleotides in length that regulate gene expression at the post-transcriptional level. They function by binding to complementary sequences in messenger RNAs (mRNAs), leading to translational repression or mRNA degradation.
In cancer, miRNA expression patterns are profoundly dysregulated. Different cancer types exhibit characteristic miRNA "signatures" — specific patterns of up- and down-regulated miRNAs that reflect the underlying biology of the tumor. This makes miRNAs powerful biomarkers for cancer detection, subtype classification, and prognosis.
- miRNAs are stable in serum, plasma, and urine — enabling liquid biopsy
- Expression changes occur early in carcinogenesis, before imaging detects tumors
- Each cancer type has a unique miRNA fingerprint
- Single miRNA profiling experiment can interrogate 600+ markers simultaneously