Identification of Specific Biomarkers for Anaplastic Thyroid Carcinoma Through Spatial Transcriptomic and Immunohistochemical Profiling.

Anaplastic thyroid carcinoma (ATC) is an aggressive malignancy with a poor prognosis. Despite its rarity, identifying predictive molecular markers that distinguish ATC from follicular cell-derived non-anaplastic thyroid carcinomas is critical for improving diagnosis and treatment strategies. This study aimed to identify and validate key mRNA and protein markers associated with ATC progression and dedifferentiation. We performed spatial transcriptomic analysis on an index case of ATC coexisting with papillary thyroid carcinoma (PTC) and identified eight differentially expressed mRNA markers. These findings were validated in a large cohort using immunohistochemistry on tissue microarrays across various thyroid tumor types, including follicular adenoma, PTC, poorly differentiated thyroid carcinoma, medullary thyroid carcinoma, and ATC. Additionally, the impact of BRAF p.V600E mutation status on these markers was evaluated. COL7A1, LAMC2, SPHK1, and SRPX2 mRNA and protein levels were significantly overexpressed in ATCs. Conversely, CD24, EPHX1, GPX3, and RBM47 mRNA and protein levels were markedly downregulated in ATCs. Functional enrichment analysis, based on mRNA expression data, identified the role of these proteins in tumor invasion, epithelial-mesenchymal transition, extracellular matrix remodeling, and immune evasion. The expression levels of these markers were independent of BRAF p.V600E mutation status, highlighting their potential as diagnostic markers. In summary, this study identified eight molecular markers that can distinguish ATC from other thyroid tumors. The validation of these markers at both the mRNA and protein levels underscores their clinical relevance in ATC diagnosis and tumor characterization. These findings provide a foundation for future biomarker-driven diagnostic and therapeutic strategies for ATC.