PYGB and central nervous system cancer: GPBB was consistently and significantly increased in high-grade glioma patients with TMZ resistance (n = 34) when compared to TMZ sensitive patients (n = 29) (mean 31.78 ng/ml, range 9.17–33.54 ng/ml vs. mean 21.42 ng/ml, range 17.61–42.96 ng/ml, P < 0.001).