Strong expression of HBME-1 associates with high-risk clinicopathological factors of papillary thyroid carcinoma.

Thyroid cancer comprises a heterogeneous group of lesions with great diversity of biological behaviour. Markers which could help clinicians to identify high-risk patients for tailored optimization of clinical management are of crucial importance. HBME-1 protein level was analysed immunohistochemically using routinely prepared archival tissue sections of a broad range of papillary thyroid carcinoma (PTC) variants and in corresponding lymph node metastases (LNM). The results were evaluated in comparison with clinicopathological features of PTC. Positive immunoreaction was noticed in most classical (83/92; 90.2 %), follicular (60/71; 84.5 %) and trabecular (4/5; 80.0 %) variants of PTC. All cases of macrofollicular, Warthin-like and diffuse sclerosing PTC variants were HBME-1 positive (4/4, 3/3, 2/2; 100 % respectively). Tall cell and solid PTC variants showed diversity of staining (2/3; 66.67 % and 13/23; 56.52 % respectively), while PTCs with mixed histological pattern containing insular areas were mainly weakly positive (2/5; 40.0 %). A single case of clear cell PTC variant showed no reaction. Moreover, all matched metastatic PTC into lymph nodes (LNM) were HBME-1 positive (17/17; 100 %) and expressed HBME-1 in a similar pattern to the matched primary tumour. We also found a statistically significant association between high HBME-1 expression and the presence of lymph node metastasis, advanced pT status and pTNM stage (P < 0.05), but only a tendency for association with extrathyroidal invasion of the tumour (P = 0.058). Therefore, we recommend using immunoexpression of HBME-1 as useful mean to increase the likelihood of detecting most PTC variants and to predict some unfavourable clinical parameters in these patients.

Expression of galectin-1 and galectin-3 in human fetal thyroid gland.

High levels of expression of galectin-1 and galectin-3, the beta-galactoside-binding proteins, have been recently described in malignant thyroid tumors but not in adenomas nor in normal thyroid tissue. However, there are no data about the expression of these galectins during fetal thyroid development. In this study we analyzed immunohistochemically the presence of galectin-1 and galectin-3 in human fetal thyroid glands (16-37 weeks of gestation). Weak to moderate cytoplasmic staining for galectin-1 was observed in follicular cells of all fetal thyroids. Galectin-3 could not be detected in thyroid follicular cells of any fetal thyroid investigated. Both galectins were detected in stromal tissue, but staining for galectin-1 was more intense. The absence of galectin-3 in thyroid cells during fetal development suggests that galectin-3 is expressed de novo during malignant transformation of thyroid epithelium, and that galectin-1 could be considered an oncofetal antigen. The results obtained indicated potential roles for galectin-1 and galectin-3 during the investigated period of human fetal thyroid gland development. Both galectins might participate in developmental processes regarding stromal fetal thyroid tissue organization, whereas galectin-1 might have a function in thyroid epithelium maturation.

Galectin-3 expression in papillary thyroid carcinoma: relation to histomorphologic growth pattern, lymph node metastasis, extrathyroid invasion, and tumor size.

BACKGROUND: Galectin-3 has been recently recognized as a promising presurgical marker of thyroid malignancy. METHODS: Galectin-3 expression was examined immunohistochemically in 202 specimens of papillary thyroid carcinoma (PTC) in relation to histomorphologic subtypes and clinicopathologic data. RESULTS.: The sensitivity of galectin-3 immunostaining versus conventional histology was 98% (100 of 102) for classical PTC, 85.2% (46 of 54) for follicular variant, and 50% (23 of 46) for follicular/solid variant of PTC. All cases (n = 36) involving lymph node metastases and 42 of 45 cases with extrathyroid invasion expressed galectin-3. However, among the galectin-3-positive cases (n = 169), 133 were without lymph node metastases, and 127 were without extrathyroid invasion. Galectin-3 expression was not related to the size of intrathyroid PTC. CONCLUSIONS: Galectin-3 immunohistochemical expression itself is not an indicator of local metastatic spread or extrathyroid invasion of PTC, thus being irrelevant clinically from this aspect. Galectin-3 is an excellent marker for classical PTC but must be used with caution in diagnosing unconventional variants of PTC because of the possibility of false-negative results.