BTK and central nervous system cancer: The correlation of BTK expression with glioma tumorigenesis (Wei et al., 2016) and with poor survival in glioma patients (Yue et al., 2017), and the discovery of a novel oncogenic BTK isoform (p65BTK) in solid tumors (Lavitrano et al., 2013; Grassilli et al., 2016), prompted the investigation of the p65BTK expression in gliomas.