Molecular Screening Test Detects Colorectal Cancer

A ribonucleic acid (RNA) screening assay detected the majority of early-stage colorectal cancers with good specificity and sensitivity.

Blood plasma samples collected from patients with early, resectable (Stage II) colorectal cancer and sex- and age-matched healthy volunteers were screened using a state of the art method for micro RNA (miRNA).

The method was based on the miRCURY locked nucleic acid (LNA) Universal reverse transcriptase miRNA polymerase chain reaction analysis. Early-stage colorectal cancer could be distinguished from healthy subjects with good sensitivity and specificity from a single plasma sample of less than 1 mL of blood.

The miRCURY LIN assays are manufactured by Exiqon A/S, (Vedbaek, Denmark). Exiqon's miRNA arrays feature normalized enhanced LNA capture probes, designed for excellent specificity and sensitivity even for AT-rich miRNAs. In addition, they offer great reproducibility with 99% correlation between arrays and a dynamic range greater than four orders of magnitude.

Colorectal cancer is the second leading cause of cancer-related deaths in the western world. If diagnosed early, the disease can usually be cured with surgery; however, the prognosis for late-stage cancer is bleak. Although several early-detection screening methods are available, current estimates suggest that less than half of Americans over the age of 50 receive adequate colorectal cancer screening. The findings were presented at the Fourth American Association for Cancer Research's International Conference on Molecular Diagnostics in Cancer Therapeutic Development that was held during September 23 – 27, 2010, in Denver (CO, USA).

Søren Jensby Nielsen, Ph.D., scientific manager, Exiqon A/S, said, "Our test has the potential to be safe, cheap, robust, accurate and of little or no inconvenience to the individual, and could, therefore, easily be integrated into national screening programs as part of an annual checkup."

Nielsen and colleagues are starting a large, prospective clinical trial in symptomatic individuals undergoing colonoscopy to validate prospectively their screening test. The scientist envision that this type of miRNA profile, once developed and marketed as a screening kit, can be used to screen entire populations in order to facilitate a focused selection of individuals who should undergo colonoscopy.

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