Nucleophosmin overexpression is associated with poor survival in astrocytoma

The multiple functions of the protein nucleophosmin (NPM) include the regulation and balance of cell growth, proliferation, and apoptosis. Many cancers have suspected associations with overexpression of NPM or with mutation of the NPM gene. Although NPM and anaplastic lymphoma kinase fusion proteins are known to be related to the Janus Kinase/Signal Transduction and Activator of Transcription (JAK/STAT) signaling pathway, the relationships of NPM, JAK2, and STAT5 to astrocytoma remain unclear. Therefore, this study performed histochemical analyses of expressions of NPM, p-JAK2, and STAT5B proteins in patients with astrocytoma. The results showed that high NPM expression was significantly associated with high tumor grade (p = 0.000), old age (p = 0.000), low Karnofsky Performance Scale (KPS) score (p = 0.000), and tumor recurrence (p = 0.045). High p-JAK2 expression was significantly associated with old age (p = 0.000), high tumor grade (p = 0.000), low KPS score (p = 0.000), and tumor recurrence (p = 0.036). Expression of STAT5B was significantly correlated with tumor grade (p = 0.018) and KPS score (p = 0.002). High expressions of NPM, p-JAK2, and STAT5B were associated with a short survival time (p = 0.035, 0.003 and 0.002, respectively). In multivariable analysis, STAT5B expression was a significant predictor of survival time (p = 0.003). In conclusion, NPM and p-JAK2/STAT5B may have important roles in tumor progression, and STAT5B is an independent prognostic marker of astrocytoma.