Abstract: Objective To investigate the key genes and their potential regulatory molecular targets of papillary thyroid carcinoma (PTC) through bioinformatics analysis, and to explore the molecular regulatory mechanism in PTC. 
Methods The gene expression profiles of PTC were retrieved and downloaded from the TCGA database, and the "Limma" software package in Rstudio was used to find out whether there was differential long non-coding RNA (lncRNA) between PTC and adjacent tissues. WGCNA was used for construction and clinical correlation analysis was performed. Enrichment analysis and annotation were performed by GSEA. 
Results After screening by the TCGA database, a total of 510 tumor tissues and 58 paracancerous tissues of PTC were included in the analysis, and a total of 58 differentially expressed lncRNAs were obtained, including 36 highly expressed genes and 22 lowly expressed genes. We used the dynamic tree cutting method to identify gene modules, set the minimum number of genes in the module to be 100, and finally obtained 11 corresponding modules. The results showed that the blue module was significantly associated with PTC. There were 34 differential lncRNAs in the blue module. Univariate and multivariate Cox regression analyses were performed on the 34 differential lncRNAs in the Blue module, and AC005479.2 was obtained. Then the receiver operating characteristic (ROC) curve was drawn for AC005479.2, with an area under the ROC curve (AUC) value of 0.838. GO and KEGG analysis revealed the potential pathways and functions of AC005479.2. The results showed that AC005479.2 might participate in cell adhesion through adipocytokine signaling pathway, MAPK signaling pathway, and cadherin binding, and positively regulate apoptosis signaling pathway, thus being involved in the pathological process of PTC. 
Conclusion There are significant differences in the expression of AC005479.2 in the thyroid tissue of PTC, patients and healthy people. The AC005479.2 gene is expected to become a biomarker gene for PTC， providing an important basis for subsequent PTC research.