Diagnostic use of molecular markers in the evaluation of thyroid nodules.

OBJECTIVE To describe the molecular markers thus far evaluated for use in the care of patients with clinically relevant thyroid nodules. METHODS We review the currently available molecular tests that have been applied to patients with thyroid nodules. RESULTS In the United States, approximately 450 000 diagnostic fine-needle aspirates will be performed on patients with thyroid nodules this year in an effort to identify thyroid cancer. Unfortunately, this test is imprecise and, at times, inaccurate. Because of this, novel diagnostic testing modalities have been pursued, the most promising of which involve molecular analysis of thyroid tissue. Immunohistochemical staining, analysis for mutations and gene rearrangements, and microarray analysis have all been investigated with regard to their performance characteristics in targeted patient populations. CONCLUSIONS Molecular tests to evaluate thyroid nodules demonstrate variable performance characteristics. Further evaluation of available and emerging molecular tests will necessarily rely on prospective real-world test validation in the clinical setting.