This week we have a blog post from Dr. Gregory Tsongalis, the 2013 winner of the AACC-NACB Award for outstanding contributions to clinical chemistry. He discusses a new entity in laboratory medicine, miRNA. While there are numerous potential applications in the literature, Dr. Tsongalis’ laboratory is one of the first to offer miRNA testing for patient care. Please join us in congratulating him on this well deserved award! The NACBlog Committee

In 1993 Victor Ambros discovered the first miRNA while at Dartmouth College, just 5 miles from the Dartmouth Hitchcock Medical Center. Some 12 years later, Carlo Croce showed the first implication of miRNAs in human cancer. Fifteen years after (2008) the discovery of miRNAs, we published our first paper in Clinical Chemistry showing the utilization of miRNA expression as a diagnostic biomarker in pancreatic cancer. In 2009, Clinical Chemistry published its first review article on this new type of analyte. Since then the field of miRNAs has been anything but small, shedding new light on biological processes, diagnostics, prognostics, and therapeutic targeting.

As a diagnostic marker, these small molecule RNAs showed great promise due to their stability and specificity for specific cell types and disease. The potential to accurately identify normal from disease tissues was more than intriguing and many labs began screening mostly cancer tissues at the time in an attempt to identify novel miRNA signatures that could be used in more accurate diagnosis and prognosis of the disease. This has since been vastly expanded to all other disease areas.

We asked the initial question as to whether these molecules could help differentiate normal or benign tissues from malignant tissues. In particular, could this be done in the initial cytology diagnostic specimen, a fine needle aspirate (FNA), instead of a resected tumor tissue. We chose to do this work in pancreatic cancer because of the necessity to often answer the question of benign vs malignant from the cytology specimens which the pathologist deemed equivocal. This landmark paper was published in Clinical Chemistry in 2008.

Today, the discovery of which genes are being regulated by specific miRNAs in specific diseases is more interesting than just the miRNA profile. In reality, identifying the miRNA profile could lead to the discovery of much better traditional biomarkers from knowing the downstream regulated genes. As such the miRNA becomes a discovery tool to screen for potential biomarkers of disease. While our knowledge about how miRNAs work is far from over, this new molecule has created much excitement with a lot of promise.