Microarray Analysis Boosts Accuracy of Thyroid Tests

The accuracy of thyroid fine-needle aspiration biopsies can be enhanced using genetic microarray technology.

Endocrinologists typically use fine needle aspiration--the nonsurgical removal of a tiny bit of tissue via needle--as their biopsy method of choice when investigating suspicious thyroid nodules. The accuracy of these tests is unsatisfactory because standard histologic (cell-based) examination in the lab cannot always distinguish cancerous or pre-cancerous tissues from samples that are benign.

In a study published in the September 2006 issue of the Journal of Molecular Diagnostics, microarray-generated gene expression profiles from fine-needle aspirates were analyzed by comparing the expression of thousands of genes from both cancerous and benign thyroid tissues. This process ended in a grouping of 25 differently expressed genes that helped distinguish malignant from benign growths.

The accuracy of these patterns was tested using 22 fine-needle aspirate samples from benign or malignant thyroid nodules. In all but one case, the microarray test agreed completely with the results of extensive histologic analysis in the lab.

Dr. Carrie Lubitz, of Weill Cornell Medical College (New York, NY, USA), lead author of the study, and Dr. Thomas J. Fahey, III, of New York-Presbyterian Hospital/Weill Cornell Medical Center (New York, NY, USA), understood that malignant and benign cells have distinct genetic patterns or "signatures” that clearly delineate one from the other. Unfortunately, scientists have only been able to test tissue for one or a few genes at a time--slowing down research and making gene-based diagnosis impractical.

"The advent of much faster microarray genetic analysis has changed all that,” Dr. Fahey said. "For patients with worrisome thyroid nodules, this means better information on whether the nodule is malignant or benign. That should help them and their doctors make better decisions as to what treatment they [would] like to pursue.”



Related Links:
Weill Cornell Medical College
New York-Presbyterian Hospital/Weill Cornell Medical Center