Blood miRNAs can affect cancer biomarker studies

Short strands of genetic material called MicroRNAs (miRNAs) are being studied more and more as potential biomarkers. However, U.S. researchers may have found a hitch--or certainly a caution--in this approach, with evidence of blood cell miRNAs 'masquerading' as cancer markers.

Because circulating miRNA is stable, easily measured and can be linked to specific diseases, it seems ideal as a biomarker, particularly in cancer. According to research carried out at the University of Washington and the Fred Hutchinson Cancer Research Institute, however, the same miRNAs linked with cancer cells could also arise from healthy blood cells.

In a literature analysis, the team found that 58% of solid tumor biomarkers reported were also highly expressed in one or more blood cell type. Increased levels of certain biomarkers were linked with raised levels of some blood cells (including following stem cell transplant, which is used as part of the treatment of certain cancers), and some miRNA levels increased by up to 50-fold when red blood cells ruptured (hemolysis).

This information shouldn't stop research into miRNAs, but rather make those studying them aware of confounding factors. As the researchers recommended, there should be "caution in interpretation of such results as they may reflect a blood cell-based phenomenon rather than a cancer-specific origin."

- check out the abstract