Expression of Autophagy-Related Proteins in Hürthle Cell Neoplasm Is Different from That in Follicular Neoplasm

PURPOSE: We aimed to evaluate expression of autophagy-related proteins in Hürthle cell neoplasm (HCN) and follicular neoplasm (FN) and assess the clinical implications. METHODS: 265 FNs (112 follicular carcinomas and 153 follicular adenomas) and 108 HCNs (27 Hürthle cell carcinomas and 81 Hürthle cell adenomas) were made into a tissue microarray. Immunohistochemical staining and Western blot for autophagy-related proteins (beclin-1, light chain (LC) 3A, LC3B, p62, and BNIP3) were performed, and the results were statistically analyzed. RESULTS: A higher expression rate of beclin-1, LC3B, p62, and BNIP3 was found in HCN than in FN (P < 0.001). The expression rate of beclin-1, LC3B, p62, and BNIP3 was the highest in HCCs followed by HCAs, FCs, and FAs in that order (P < 0.001). HCCs were positive for the largest number of autophagy-related proteins followed by HCAs, FCs, and FAs (P < 0.001), and most of the positive markers identified in HCCs were the high autophagy type (P < 0.001), defined by positive staining for three or more of the five autophagy-related proteins. CONCLUSION: The autophagy-related proteins, beclin-1, LC3A, LC3B, p62, and BNIP3, were more frequently expressed in HCNs than in FNs, and HCCs showed the highest expression rate.