(A) mRNA levels of SDC4 in each cell line; *p < 0.05, vs. normal thyroid cells; #p < 0.05, vs. BCPAP and IHH-4 cell lines; the experimental data were measurement data; the one-way ANOVA was used to analyze data; the experiment was repeated 3 times. (B) mRNA levels of SDC4, Wnt3a, β-catenin, Bcl-2, Bax, E-cadherin, Vimentin, and N-cadherin and Axin2 in K1 and TPC-1 cell lines detected by RT-qPCR; RT-qPCR, reverse transcription quantitative polymerase chain reaction; SDC4, Syndecan 4; PTC, papillary thyroid carcinoma; EMT, epithelial mesenchymal transition; NC, negative control; Bcl-2, B-cell lymphoma-2; Bax, Bcl-2-Associated X; ANOVA, analysis of variance; *p < 0.05, vs. the blank group; #p < 0.05, vs. the si-SDC4 group; the experimental data were measurement data; the one-way ANOVA was used to analyze data; the experiment was repeated 3 times.