ANXA5 and glioblastoma: By contrast, U118 cells (3.9–6.34% AnnexinV+ P=0.33) and U373 cells (2.9–3.1% AnnexinV+ P=0.88) did not show significant differences in apoptotic cell number following exposure to Fsk–IBMX, demonstrating a selective response to cAMP-induced cell death among the four GBM cell lines examined (Figure 4a).