Protein Expression of Glucose Metabolism and Somatostatin Receptor Between Primary Tumor and Distant Metastasis in Differentiated Thyroid Cancer

This study evaluated differences in the expression of proteins related to glucose metabolism and somatostatin receptors (SSTRs) between primary tumors and distant metastatic lesions in differentiated thyroid cancer (DTC). We retrospectively analyzed 18 patients with DTC (mean age 56 ± 10 years) who had bone or soft tissue metastasis. Immunohistochemical staining of surgical specimens was performed to assess the expression of glucose transporter 1 (GLUT-1), hexokinase-2 (HK-2), and somatostatin receptor subtype 2 (SSTR-2). Protein expression was classified as negative, weakly positive, or strongly positive. Correlations between primary and metastatic lesions were evaluated using Spearman analysis. FDG SUVmax values were compared according to protein expression using the Mann–Whitney U test, and the association between iodine avidity and SSTR-2 expression was assessed using Fisher’s exact test. GLUT-1 expression was more frequent in metastatic lesions than in primary tumors (65