KCNN4 was overexpressed in PTC. (A–D) KCNN4 mRNA levels were greater in PTC tissues than in normal thyroid tissues in GSE58689, GSE3678, GSE9115 and TCGA. (E) KCNN4 was upregulated in 70 PTC tissues compared with matched adjacent nontumorous thyroid tissues from our RNA sequencing dataset. (F) The overexpression of KCNN4 in PTC was verified in our validated cohort using qRT-PCR. Statistical analyses were performed as follows: (A, C, D): Mann-Whitney test; (B): Paired t-test; (E, F): Wilcoxon test. **p<0.01, ****p<0.0001.