Treatment of two SF3B1 mutant cell lines, Panc 05.04 (pancreatic, K700E) and ESS-1 (endometrial, K666N), and six wild-type controls (three pancreatic and three endometrial) with an SF3b complex inhibitor, spliceostatin A, revealed that SF3B1 mutant cell lines were significantly more sensitive to this agent (p = 0.0118, t-test, Figure 3A).