BDNF and astrocytoma (excluding glioblastoma): Based on published results obtained on human astrocytoma cell lines used to examine the molecular signaling and mechanisms connected with protection of neuronal cells (Wagoner et al. 1999; Deb et al. 1999; Nischiguchi et all., 1999; Mori et al. 2008; Wang et al. 2010a, b; Yoshida et al. 2011; Li et al. 2014; Saeed et al. 2015), the purpose of the present study was to investigate the ability of proline-rich polypeptide complex PRP and its nonapeptide fragment NP to up-regulate the secretion of neurotrophins on the model of human astrocytoma cell line U87.