SF3B1 and B-cell chronic lymphocytic leukemia: To calculate PSI for the 325 proximal cryptic 3’SSs used significantly more often in the SF3B1 mutants from the CLL-only analysis (S6–S7 Files), we divided the number of reads that span the cryptic 3’SS by the number of reads that span both the cryptic 3’SS and its associated canonical 3’SS.