The incidence of papillary thyroid carcinoma (PTC) is rapidly increasing, and it is urgent to find new biomarkers for treatment and prognosis. The Kinesin family plays an essential role in tumorigenesis and development, as a therapeutic target in a variety of tumors. In this study, based on a public database, the effect of KIF23 on the prognosis of PTC was preliminarily analyzed. It was found that compared with normal tissues, the GEPIA database showed the up-regulated expression of KIF23 gene in thyroid cancer. Two PTC cohorts were downloaded from The Cancer Genome Atlas (TCGA), and survival analysis was performed by Kaplan-Meier method. It was found that the prognosis of the group with high KIF23 expression was worse than that of the group with low KIF23 expression. Immunohistochemical methods were used to detect the expression and clinicopathological features of KIF23 in 67 thyroid cancer tissues. The results further confirmed the up-regulation of KIF23 expression in thyroid cancer cells. Subsequently, knockdown of KIF23 was performed in thyroid cancer

cells, and the expression of KIF23 in thyroid cancer cells was confirmed by RT-qPCR and western blot. The effect of KIF23 on the proliferation of PTC cells was analyzed by colony formation assay and CCK-8 detection. The results showed that the proliferation of thyroid cancer cells was significantly inhibited after KIF23 knockdown expression. The results of this study suggest that the expression of KIF23 is related to the clinicopathological proliferation of thyroid cancer cells. Knockdown of the KIF23 gene can inhibit the pathological proliferation of thyroid cancer cells, which may be a therapeutic target in the future. High expression of KIF23 can serve as a molecular marker for poor prognosis in patients with PTC.