Expression of CD30 Ligand and CD30 Receptor in Normal Thyroid and Benign and Malignant Thyroid Nodules

Because the CD30 ligand (CD30L)/CD30 receptor (CD30) system is expressed in certain malignancies, but has not been studied in thyroid nodules, we investigated its immunohistochemical expression in 6 normal thyroids (NT) and 131 thyroid nodules: 28 colloid nodules (CN), 45 adenomas (15 oncocytic [OA], 30 follicular [FA]) and 58 carcinomas (15 follicular [FTC], 1 insular [ITC], 6 anaplastic [ATC], 30 papillary [PTC], and 6 medullary [MTC]). NT and CN expressed neither CD30L nor CD30 (CD30L^-/CD30^-). Forty percent of OA and 20% of FA showed epithelial coexpression of CD30L and CD30, and interstitial expression of CD30L, which was also observed in the surrounding normal tissue. Within malignancies, epithelial coexpression of CD30L and CD30 was observed in 7% of FTC, 33% of ATC, 67% of PTC, and 67% of MTC. Only PTC and MTC showed epithelial expression of CD30L in the perinodular tissue with similar frequency (80% PTC, 75% MTC). PTC and MTC had the highest proportion of CD30L⁺ or CD30⁺ cells, and together with OA, a thus far unreported nuclear location of CD30L. In PTC, the proportion of CD30L⁺ cells and the prevalence of nuclear location of CD30L correlated inversely and directly, respectively, with aggressiveness. In conclusion, CD30L/CD30 signaling is activated only past the colloid nodule stage, most frequently in an autocrine fashion.