Cyclin A and cyclin B1 overexpression in differentiated thyroid carcinoma

Approximately 30% of patients with thyroid nodules have indeterminate or suspicious fine-needle aspiration (FNA) biopsy results. These patients usually undergo thyroidectomy because of cancer risk. Our aim was to determine diagnostic value of cyclin A and cyclin B1 immunohistochemistry added to routine cytology and their expression on histological sections. We studied the expression of cyclin A and cyclin B1 in FNA biopsies and resection specimens of 168 indeterminate or suspicious FNA biopsy results retrospectively at an academic hospital using immunohistochemistry. Malignant histopathology consisted 64 of resection specimens (58 papillary, 4 follicular, 1 medullary, and 1 Hurthle cell carcinoma). Cyclin A was overexpressed in 51.5% of malignant cases in contrast to 31.7% of 104 benign pathology specimens (P = 0.025). Cyclin B1 was positive in 39.1% of malignant specimens in contrast to 15.4% of benign cases (P = 0.001). Cyclin A overexpression was not linked to cyclin B1 overexpression. No association was found between overexpression of cyclin A, cyclin B1 and age, thyroiditis, multifocality, tumor size, extra-thyroidal extension, capsule infiltration, lymph node and distant organ metastases and TNM stage in malignant cases. Female patients with thyroid carcinoma overexpressed significantly more cyclin B1 than male patients (P = 0.015). Retrospective analysis of cyclin A and cyclin B1 in FNA biopsies yielded negative results for both benign and malignant cases. In conclusion, cyclin A and cyclin B1 are useful markers in the distinction of benign and malignant thyroid tumors and can increase diagnostic accuracy.