CLN5 and glioma: The specific focus of this review is the role of BMP proteins and their receptors in astrocytic glioma pathogenesis because: (1) some members of the BMP family of ligands have been found differentially expressed in tumors versus healthy tissue with a neat clinical relevance, (2) activation of the BMP pathway reduces glioma cell proliferation in vitro and in vivo and induces differentiation of the glioma initiating cells (GICs), and (3) BMPs render GICs more susceptible to conventional therapy, so BMP treatment is being considered as a promising therapeutic tool against GBM.