Newswise — MicroRNA (miRNA) expression profiles can be used to identify an aggressive type of papillary thyroid cancer that is often otherwise difficult to detect, according to data to be presented on Oct. 2, 2008 at the 79th Annual Meeting of the American Thyroid Association (ATA) in Chicago, IL.

miRNAs are a class of small RNA molecules that regulate a broad array of physiological and developmental processes. miRNAs have been shown to be highly sensitive and tissue specific biomarkers for various cancers, with some of them serving as prognostic indicators.

A team of researchers from University of Pittsburgh led by Marina N. Nikiforova, M.D., studied six papillary thyroid carcinomas from patients with local tumor recurrence or distant metastases to determine if miRNA markers predicted a more aggressive tumor behavior. Researchers compared these tumors with similar patients' tumors that had no complications. Expression profiling of 328 human mature miRNAs was performed on both tumor groups and analyzed using the Flexmir MicroRNA Human Panel.

Researchers found that while the tumors in both groups had relatively similar expression profiles, a number of miRNAs were significantly more overexpressed in aggressive tumors, including miR-155, which has been shown to confer a poor prognosis in other tumor types. Researchers also found several other miRNAs that were downregulated only in aggressive papillary thyroid cancers. In addition, researchers also found miRNAs targeting the MET gene, which may serve as a mechanism for MET overexpression previously identified in these tumors.

"These data show that miRNA profiling holds promise as an effective tool to detect aggressive types of papillary thyroid cancer" said Dr. Nikiforova, principle investigator of the study. "This is an important discovery because aggressive papillary thyroid cancer is not only difficult to diagnose, but is very challenging to treat, particularly once the cancer has progressed."

About the American Thyroid Association (ATA)The American Thyroid Association (ATA) is the lead organization in promoting thyroid health and understanding thyroid biology. The ATA values scientific inquiry, clinical excellence, public service, education, collaboration, and collegiality.

A non-profit medical society founded in 1923, the ATA fulfills its mission through supporting excellence and innovation in research, clinical care, education, and public health. ATA members are physicians and scientists who work to enhance the understanding of thyroid physiology and pathophysiology, improve the diagnosis and treatment of thyroid diseases, and promote the education of physicians, patients, and the public about thyroid disorders.

Thyroid diseases are among the most common disorders of the endocrine system, affecting almost 13 million Americans alone. The ATA has extensive online information for patients on thyroid disease (in English and Spanish) serving the clinician as a resource for patients and the public who look for reliable information on the internet.

To learn more about the ATA, visit:

Presentation of this research at the ATA Annual Meeting is thought to be of interest to the public, however, this does not necessarily imply official endorsement by the ATA.

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79th Annual Meeting of the American Thyroid Association