BCL2L1 and glioblastoma: Likewise, PSI determination confirmed previous results since pladienolide B treatment reduced BCL2L1 alternative 5′ end splice site (A5SS) splicing event in U-87/U-118 MG cells (Fig. 9j), primary-GBM cell -cultures (Fig. 9k), and in the preclinical-xenograft GBM model (Fig. 9l).