Abstract

Background: Papillary thyroid cancer is a common head and neck malignancy with a globally rising incidence. While most patients attain favorable prognosis following standard treatment, a subset develops recurrence and metastasis—two key factors that compromise clinical outcomes. Anoikis resistance is a prerequisite for tumor metastasis; however, the role and mechanism of Fibronectin 1 (FN1)—a molecule overexpressed in multiple cancers and linked to tumor progression—in papillary thyroid cancer anoikis resistance remain undefined. Objective: This study therefore investigated the function and regulatory mechanism of FN1 in papillary thyroid cancer anoikis resistance using a combination of bioinformatics analyses and experimental validation. Methods: First, using The Cancer Genome Atlas (TCGA) dataset and anoikis-related genes from GeneCards, we identified FN1 as an anoikis-related hub gene in thyroid cancer through bioinformatics analyses, including consensus clustering, weighted gene co-expression network analysis (WGCNA), and protein-protein interaction (PPI) network analysis. Its clinical relevance was further analyzed from the perspectives of pathological typing, survival prognosis, immune cell infiltration (via xCell) and single-cell expression patterns. Next, we performed validation using papillary thyroid cancer tissues, adjacent normal tissues, and cell lines (8305c, BCPAP, Nthy-ori 3 − 1): FN1 expression and cancer cell anoikis were detected by immunohistochemistry (IHC) and TUNEL staining; FN1 mRNA and protein levels were quantified via qRT-PCR and Western blot. Finally, we modulated FN1 expression through RNA interference (for knockdown). Cell proliferation, migration, and invasion were assessed using CCK-8 and Transwell assays, while Western blot was applied to measure the expression of apoptosis-related proteins. Results: FN1 is highly expressed in papillary thyroid cancer tissues and cell lines and is associated with poor tumor prognosis. Silencing FN1