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Updated: Apr 18, 2026

Spontaneous Murine Model of Anaplastic Thyroid Cancer
Published on: February 3, 2023
Altered expression of claudin-1 is related with malignancy in canine thyroid tumors
Ana Rute Flores1, Alexandra Rêma1, Irina Amorim2
1Department of Pathology and Molecular Immunology of the Institute of Biomedical Sciences Abel Salazar (ICBAS), University of Porto, Porto, Portugal.
Background/Aim:
Claudins (CLDNs) are crucial structural and functional components of tight junctions playing an important role in maintaining cell polarity, controlling paracellular diffusion and regulating cell growth and differentiation of epithelial cells. CLDNs are differentially expressed in neoplastic lesions compared to the corresponding healthy tissues; therefore, they are thought to play a role in tumorigenesis and tumor progression. Reduced expression of CLDN-1 has been observed in several types of human cancers, including thyroid tumors. There are no reports of CLDN-1 immunoexpression in normal and neoplastic canine thyroid tissues.
Material And Methods:
CLDN-1 immunoexpression was investigated in normal canine thyroid gland (n=2), benign (n=1) and malignant (n=10) tumors, as well as neoplastic emboli (n=6).
Results:
CLDN-1 was constitutively expressed in normal canine follicular epithelium. Ninety percent of the malignant canine thyroid lesions showed absence or reduced CLDN-1 expression compared to that of normal thyroid gland. Additionally, a cytoplasmic subcellular location of CLDN-1 was recorded in the malignant epithelial cells and neoplastic emboli.
Conclusion:
These findings link altered expression of CLDN-1 to neoplastic transformation and suggest that CLDN-1 expression is associated with malignant canine thyroid tumors and their vascular invasion.
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