A highly sensitive blood test can detect cancer related micro-ribonucleic acid (miRNA) before any signs of the disease manifests.
Increased expression of circulating miRNAs could be indicative of miRNAs secreted from a tumor, raising the overall diagnostic specificity of biomarkers, especially if they can be measured in blood or serum samples.
Scientists at the Baylor Research Institute (Dallas, TX, USA) analyzed 568 serum and tissue specimens that were obtained from healthy volunteers and consecutively enrolled patients with colorectal adenomas and cancers at the Mie University Medical Hospital (Tsu, Japan), between January 1, 2005 and December 31, 2010.
MiRNA extraction from serum and culture media samples was performed with miRNeasy RNA isolation Kits (Qiagen; Valencia, CA, USA), whereas miRNA extraction from formalin-fixed and paraffin-embedded (FFPE) samples was performed using RecoverAll Total Nucleic Acid Isolation Kits (Ambion Inc.; Austin, TX, USA). The TaqMan miRNA quantitative reverse-transcription polymerase chain reaction (qRT-PCR; Applied Biosystems; Foster City, CA, USA) were used to detect and quantify miRNA expression.
By measuring levels of miR-21 in the blood, the scientists could accurately identify up to 92% of patients with colorectal cancer. Even more importantly, not only is this test good for noninvasively identifying patients who already have colorectal cancer, but it can accurately identify up to 82% of patients with advanced colonic polyps, which present the highest risk for developing into colorectal cancers several years later in life.
Ajay Goel, PhD, the lead investigator said, “The development of this biomarker is highly encouraging because high mortality rates associated with colorectal cancer is a consequence of late detection of this disease, underscoring the need for improved early detection, prevention, risk assessment, and intervention. Michael Ramsay, MD, the president of Baylor Research Institute, added, “This blood-based test could be transformative in how we screen patients for colorectal cancer; it would save lives and could result in major savings of health care dollars.” The study was published on May 23, 2013, in the Journal of the National Cancer Institute.