Prognostic significance of p53 expression in malignant bone tumors: a meta-analysis. Osteosarcoma and Ewing's sarcoma are the two most common primary malignant bone tumors, and findings of prognostic factors are important for clinicians to decide treatment options. High p53 expression has been implicated in tumor development and progression, but studies investigating the prognostic role of p53 overexpression in malignant bone tumors report conflicting findings. We performed a meta-analysis to assess the relationship between p53 overexpression and the survival of malignant bone tumors. A meta-analysis of 13 studies with a total of 703 patients was carried out to evaluate the association between p53 overexpression and overall survival (OS) and disease-free survival (DFS) in patients with malignant bone tumors. The pooled hazard ratio (HR) with its 95 % confidence interval (CI) was used as the effect size estimate. There was no between-study heterogeneity in both OS studies (I (2) = 0.0 %) and DFS studies (I(2) = 0.0 %). Overall, high p53 expression predicted both poor OS (HR 2.13, 95 % CI 1.81-2.52, P < 0.001) and poor DFS (HR 2.06, 95 % CI 1.58-2.69, P < 0.001) in patients with malignant bone tumors. Subgroup analyses by tumor types suggested that p53 expression predicted poor OS in both osteosarcoma patients (HR 2.15, 95 % CI 1.78-2.60, I (2) = 15.2 %, P < 0.001) and Ewing's sarcoma patients (HR 2.09, 95 % CI 1.47-2.97, I(2) = 0.0 %, P < 0.001). Besides, p53 expression also predicted poor DFS in both osteosarcoma patients (HR 2.38, 95 % CI 1.60-3.52, I(2) = 0.0 %, P < 0.001) and Ewing's sarcoma patients (HR 1.83, 95 % CI 1.28-2.63, I(2) = 0.0 %, P = 0.001). Egger's test also did not suggest evidence for publication bias in both OS studies (P = 0.615) and DFS studies (P = 0.258). High p53 expression indicates a poorer prognosis for patients with osteosarcoma and Ewing's sarcoma.