Genetic Analysis in Diagnosing Thyroid Cancer in Patients With Thyroid Nodules

OBJECTIVES: * Evaluate the diagnostic accuracy of biomarkers and mRNA expression analysis using fine-needle aspiration (FNA) biopsy samples from patients with thyroid nodules. * Correlate the level of gene expression with the aggressiveness of differentiated thyroid cancer in FNA biopsy samples. OUTLINE: Patients undergo fine-needle aspiration (FNA) biopsy as part of routine care. Additional thyroid tissue is collected during the biopsy for gene expression analysis. Patients who have already had a biopsy undergo FNA biopsy during thyroidectomy. Tissue samples will be examined for gene expression by reverse transcriptase-polymerase chain reaction (PCR), real-time quantitative PCR, and immunohistochemistry. PROJECTED ACCRUAL: A total of 400 patients will be accrued for this study.