On the other hand, there are good prognostic factors, such as PTEN, which was highlighted by Zhou et al. in a review of 13 articles that included 580 patients with osteosarcoma; a positive expression of PTEN was associated with a better prognosis, including a lower incidence of metastasis and larger differentiated tumours, which were, therefore, less aggressive [40]. The gene discussed is PTEN; the disease is neoplasm.