Therefore, U2AF1R156H and U2AF1Q157(P/R) patient samples were grouped together (N=4–5 U2AF1R156H/Q157(P/R) patients per study; Fig. 7A) consistent with previous studies demonstrating similar 3’SS sequence dependencies.21,22 In each study, samples from MDS/AML patients who did not have identifiable mutations in SF3B1 or SRSF2 were used as a comparator (Splicing Factor [SF]WT). Here, SF3B1 is linked to myelodysplastic syndrome.