BACKGROUND The aim of this study was to investigate STMN1 and MKI67 expression in uterine leiomyosarcoma and their potential roles as biomarkers for diagnosis. MATERIAL AND METHODS The expression of STMN1 and MKI67 mRNA in uterine leiomyosarcoma were investigated in TCGA database. The overall survival (OS) and disease-free survival (DFS) were compared between high and low expression groups. Seventy-two patients who received hysterectomy were included and divided into 4 groups: uterine normal smooth muscle tissue (UNSM=30), uterine leiomyoma (UL=30), uterine cellular leiomyoma (UCL=24), and uterine leiomyosarcoma (ULS=18). The STMN1 and MKI67 protein expression of the 4 groups were examined by immunohistochemistry (IHC) assay. RESULTS The expression level of STMN1 mRNA in cancer tissue was significantly higher than those of normal uterine smooth muscle tissue. The high and low expression of STMN1 and mki67 gene mRNA was not related to the patients' OS and DFS (P>0.05). The positive rate of STMN1 protein in uterine leiomyosarcoma was 100.00%, which was significantly higher than that of the other 3 groups (χ²=11.72, P=0.008). And the positive rate of KIM67 protein in uterine leiomyosarcoma was 77.78%, which was also significantly higher than that of the other 3 groups (χ²=48.89, P=0.000). The diagnostic sensitivity and specificity were 77.78%, 90.74% for STMN1 combined MKI67 with the positive predictive value and negative predictive value of 73.68% and 92.45%, respectively. CONCLUSIONS STMN1 and MKI67 were upregulated in uterine leiomyosarcoma and act as potential biomarkers for uterine leiomyosarcoma diagnosis.