An Immunohistochemical Study of Stathmin 1 Expression in Osteosarcoma Shows an Association with Metastases and Poor Patient Prognosis.

BACKGROUND Osteosarcoma is the most common primary bone cancer and has a broad spectrum of histological subtypes. Stathmin 1 (STMN1) is a cytosolic phosphoprotein that is expressed in several types of cancer. The aim of this study was to evaluate the expression levels of STMN1 in osteosarcoma with clinicopathological characteristics and patient prognosis. MATERIAL AND METHODS The expression of STMN1 in tumor tissue from 94 patients with OS was detected and evaluated using an immunohistochemical score to divide the patients into low expression and high expression groups. Correlation between STMN1 expression and clinicopathological factors were analyzed with Fisher's test, the prognostic value of expression levels of STMN1 in tumor tissue was evaluated by Kaplan-Meier univariate analysis, and independent prognostic factors were identified using the Cox regression model. RESULTS Low expression of STMN1 was found in 43.62% of cases and high expression of STMN1 was found in 56.38% of cases of osteosarcoma. High tumor expression of STMN1 was significantly associated with the presence of metastases (P=0.028), Enneking surgical stage (P=0.030), tumor response to chemotherapy (P=0.011), and the site of tumor origin (P=0.023). High tumor expression of STMN1 was a prognostic marker in patients with osteosarcoma for poor prognosis (P=0.016), poor response to chemotherapy (P=0.004), the presence of metastases (P=0.003), advanced Enneking surgical stage (P=0.014), and the chondroblastic osteosarcoma subtype (P=0.004). The expression STMN1 was identified as an independent prognostic biomarker of osteosarcoma. CONCLUSIONS Increased expression of STMN1 in tumor tissue was an independent prognostic biomarker in patients with osteosarcoma.