To test the functional interaction between Bcl-2, Bcl-xL, and HRK in GBM cells, we first examined endogenous levels of Bcl-2 and Bcl-xL expression and observed that A172 cells expresses elevated levels of both Bcl-2 and Bcl-xL compared to LN18, U87MG, and U373 cells (Fig. 2a, b). Here, HRK is linked to glioblastoma.