Diagnostic Value of Galectin-3 in Distinguishing Invasive Encapsulated Carcinoma from Noninvasive Follicular Thyroid Neoplasms with Papillary-Like Nuclear Features (NIFTP)

Histopathological Assessment for Papillary Thyroid Carcinoma

Histologic assessments of papillary thyroid carcinoma are crucial for management of patients with the cancer as well as research on the cancer as papillary thyroid carcinoma has different histologic subtypes and many parameters which are essential in predicting the biological aggressiveness of the cancer. The histologic assessments should be guided by universally adopted protocols including World Health Organization (WHO) classification of endocrine tumors, International Collaboration on Cancer Reporting (ICCR) dataset, American Thyroid Association initial risk stratification for differentiated thyroid carcinomas and TNM stage groupings. The essential steps in histologic assessment involve the identification of characteristic features of papillary thyroid carcinoma, correct histologic subtyping, noting the number of carcinomas, measuring the size of the carcinoma, documenting the different aggressive histological parameters (mitotic activity, presence of tumor encapsulation/circumscription, lymphatic vessel invasion, blood vessel invasion, necrosis, extrathyroidal extension), resection margin status, associated pathology, presence of parathyroid gland, lymph node and distant metastases as well as synthesis of pathological stage based on the various clinical, macroscopic, and histological features.

Galectin-3 Contributes to the Inhibitory Effect of lα,25-(OH)2D3 on Osteoclastogenesis

The active form of vitamin D, 1α,25-(OH)₂D₃, not only promotes intestinal calcium absorption, but also regulates the formation of osteoclasts (OCs) and their capacity for bone mineral dissolution. Gal-3 is a newly discovered bone metabolic regulator involved in the proliferation, differentiation, and apoptosis of various cells. However, the role of galectin-3 (gal-3) in OC formation and the regulatory effects of 1α,25-(OH)₂D₃ have yet to be explored. To confirm whether gal-3 contributes to the regulatory effects of 1α,25-(OH)₂D₃ on osteoclastogenesis, osteoclast precursors (OCPs) were induced by macrophage colony stimulating factor (M-CSF) and receptor activator of nuclear factor κB ligand (RANKL). TRAP staining and bone resorption analyses were used to verify the formation and activation of OCs. qPCR, Western blotting, co-immunoprecipitation, and immunofluorescence assays were used to detect gene and protein expression. The regulatory effects of gal-3 in OC formation after treatment with 1α,25-(OH)₂D₃ were evaluated using gal-3 siRNA. The results showed that 1α,25-(OH)₂D₃ significantly increased gal-3 expression and inhibited OC formation and bone resorption. Expression levels of OC-related genes and proteins, matrix metalloproteinase 9 (MMP-9), nuclear factor of activated T cells 1 (NFATc1), and cathepsin K (Ctsk) were also inhibited by 1α,25-(OH)₂D₃. Gal-3 knockdown attenuated the inhibitory effects of 1α,25-(OH)₂D₃ on OC formation, activation, and gene and protein expression. In addition, gal-3 was co-localized with the vitamin D receptor (VDR). These data suggest that gal-3 contributes to the osteoclastogenesis inhibitory effect of lα,25-(OH)₂D₃, which is involved in bone and calcium homeostasis.

Immunohistochemistry Helps to Distinguish Noninvasive Follicular Thyroid Neoplasm with Papillary-like Nuclear Features/Noninvasive Encapsulated Follicular Variant of Papillary Thyroid Carcinoma with Other Follicular Thyroid Lesions

Background and Objectives: We aimed to assess the diagnostic value of various immunohistochemical (IHC) markers and panels for differentiation among benign follicular nodules (BFNs), noninvasive follicular thyroid neoplasms with papillary-like nuclear features (NIFTPs), noninvasive encapsulated follicular variants of papillary thyroid carcinoma (NEFVPTCs), and infiltrative FVPTC (IFVPTC). Materials and Methods: Sixty-three cases were classified as BFNs, NIFTPs, NEFVPTCs, or IFVPTCs and were evaluated using the following markers: CK19, CD56, galectin-3, CITED1, HBME-1, VE1, and TROP-2. Results: The IHC results for NIFTP and NEFVPTC exhibited no statistically significant differences. In differentiating IFVPTCs from BFNs and NIFTPs/NEFVPTCs, galectin-3 and TROP-2 were the markers with the highest sensitivity plus high specificity, respectively. In various combinations, panel co-expression of two markers, including galectin-3 and/or HBME-1 and/or TROP-2, and the combination of galectin-3 and TROP-2 co-expression could achieve 100% in all aspects. In terms of discrimination of BFNs from NIFTP/NEFVPTC, CK19 was the single most sensitive marker (81.3%), while CD56 was the most specific (100%). The panel consisting of CK19 and/or HBME-1 exhibited the greatest sensitivity (96.9%), but the panel with CD56 and/or HBME-1 exhibited the greatest specificity (90.5%). Conclusions: Our results broaden the use of IHC markers for differential diagnoses among the four groups of follicular-based lesions. In addition, the similar IHC profiles of NIFTP and NEFVPTC also suggest the original criterion of <1% papillae within tumors, providing a reliable NIFTP diagnosis. Their close relationship may represent a spectrum of progressing neoplasia.