MicroRNA profiling may predict aggressive papillary thyroid carcinomas

79th Annual Meeting of the ATA

CHICAGO — High levels of microRNA-155 overexpression appeared to indicate tumor aggressiveness in thyroid papillary carcinomas, according to the findings of a recent study presented at the 79th Annual Meeting of the American Thyroid Association, held here.

“Papillary thyroid carcinomas with specific genetic abnormalities show different microRNA profiles,” Marina N. Nikiforova, MD, PhD, assistant professor of Molecular Anatomic Pathology at the University of Pittsburgh said during a presentation.

MicroRNAs are dysregulated in various tumor types, and some serve as markers of poor prognosis, according to the study abstract. “In this study, we searched for microRNA markers of more aggressive behavior in papillary thyroid carcinomas,” the researchers wrote.

“It is important to predict aggressive tumor behavior in early stages of disease for optimal patient therapy,” Nikiforova said.

The researchers compared aggressive papillary thyroid cancers that had local tumor recurrence or distant metastases (n=6) with tumors that had no complications (n=6).

The tumors in both groups demonstrated similar expression profiles; the most highly overexpressed microRNAs were miR-146b, miR-221 and miR-222, according to the researchers. The most down-regulated in both groups were miR-153, miR-448, miR-325, miR-382 and miR-495.

In aggressive papillary thyroid carcinomas, miR-155, miR-205 and miR-337 were significantly more overexpressed. miR-376a, miR-376b, miR-422a and miR-130b were down-regulated in aggressive papillary thyroid carcinomas only, according to the researchers.

MicroRNAs targeting the MET gene were down-regulated in aggressive papillary thyroid cancers. – by Christen Haigh

For more information:
Nikiforova MN, Aspden LM, Dipaola JE, Nikiforova YE. #4. Presented at: 79th Annual Meeting of the American Thyroid Association; Oct. 1-5, 2008; Chicago.