Osteosarcoma metastasis: prospective role of ezrin

Osteosarcoma is the most commonly diagnosed primary malignant bone tumor, with similar global incidence rate across childhood and adolescence. Patients with localized disease have a 5-year survival period of 80 %; however, the prognosis is poor in those with metastatic osteosarcoma. The origin of the primary tumor is most frequently the metaphyseal (actively growing) regions of the distal femur, proximal tibia, and proximal humerus, although the tumor can develop in any bone, and the most likely sites for metastasis are the lungs and bone. Ezrin is a member of the ezrin-radixin-moesin (ERM) family of proteins that functions as a cross-linker between the actin cytoskeleton and the plasma membrane, and ezrin also plays a positive role in maintaining cell shape and polarity and facilitates membrane-trafficking pathways, cell migration, cell signaling, growth regulation, and differentiation. There is strong evidence to suggest that ezrin is necessary for osteosarcoma metastasis. The objective of the current review is to summarize the know-how about metastatic progression in osteosarcoma, with a focus on ezrin. Despite the promise that preliminary studies on ezrin have shown, there is a great need to further analyze the role of ezrin in osteosarcoma metastasis and to determine its usefulness as a biomarker for the disease.