ABSTRACT
PURPOSE: Recent studies indicate that Fas and Fas Ligand (Fas-L) are implicated in autoimmune endocrine diseases and tumors of the thyroid. In this study we tried to elucidate the expression stati of Fas and Fas-L in some kinds of thyroid neoplasms, and their relationships with 4 prognostic factors in papillary thyroid cancer (i.e., size, lymph node metastasis, capsule invasion, age). METHODS: 66 cases of thyroid neoplasm including 45 cases of papillary cancer (PTC), 3 of a follicular cancer (FTC), 1 of a poorly differentiated cancer (PDC), 1 of a undifferentiated cancer (UC), 7 of follicular adenoma (FA), and 9 of nodular hyperplasia (NH) were examined, and estimated as negative, weak positive and strong positive about the Fas and Fas-L expression by the immunohistochemical staining intensities. We then collected and compared the differrences between benign and malignant tumors. The expressions of Fas and Fas-L in papillary thyroid cancers were evaluated relating to the differences in the prognostic factors (i.e., the size, lymph node status, capsule invasion, and age of the patients). RESULTS: Malignant thyroid tumors revealed stronger staining intensity than benign neoplasms. In papillary thyroid cancers, Fas-L staining intensities were significantly stronger in the cases with perithyroidal lymph node metastasis, or in those of 45 years old or over than in those with no lymph node metastasis, or younger than 45 years. CONCLUSION: Both Fas and Fas-L are implicated in thyroid tumorigenesis and revealed stronger staining intensities in malignant than benign tumors, and the Fas-L staining intensities may have some prognostic implications at least in papillary thyroid cancers.