[1147] Cyclin D1 Expression in Clinical (>1.0 cm) and Micro-Papillary Thyroid Carcinoma

M Tetzlaff, T Pasha, K Montone, VA LiVolsi, ZW Baloch. University of Pennsylvania, Philadelphia, PA

Background: Cyclin D1 is a G1 cyclin that is essential for the regulation of G1/S transition through the cell cycle. Increased expression of cyclin D1 has been demonstrated in various human tumors including thyroid neoplasms. In this immunohistochemical study, we examined the expression of cyclin D1 in papillary thyroid carcinoma and its variants, especially microcarcinoma.
Design: Sixty-two cases of clinical papillary carcinoma (CLPTC) i.e. measuring >1.0 cm (20 classic variant, 36 follicular variant, 5 tall cell variant and 1 diffuse sclerosis variant), 39 papillary microcarcinoma (MiPTC) and 11 lymph nodes with metastatic papillary carcinoma in 46 patients (32 females and 14 males; age range 21-77 yrs) were examined for cyclin-D1 expression by immunohistochemistry. Twenty-six cases of MiPTC showed multifocal disease. All cases had a significant surrounding benign thyroid parenchyma and a majority demonstrated chronic lymphocytic thyroiditis. The nuclear imunoreactivity was graded semi-quantatively on a sliding scale as 0 = no staining, focal = 0-<25% of the cells showing positive staining and diffuse =>25% of the cells showing positive staining.
Results: Diffuse nuclear staining was seen in 57/62 (92%) CLPTC, 34/39 (87%) MiPTC and 11/11 (100%) metastatic deposits in lymph nodes; strong immunostaining was seen at invasive edge of the tumors with extrathyroidal extension. In particular 32/36 (89%) cases of follicular variant of PTC (FVPTC) showed diffuse staining. Normal thyroid parenchyma showed no immunostaining; focal immunostaining was seen in two cases in foci of chronic lymphocytic thyroiditis.
Conclusions: There is no difference in cyclin D1 gene expression among PTC and MiPTC. According to this study its expression may be of value in diagnostically challenging cases of PTC especially FVPTC in cytology and surgical pathology.
Category: Head & Neck

Monday, March 9, 2009 1:00 PM

Poster Session II # 182, Monday Afternoon