...MCL pts treated with single agent acalabrutinib (n=28) in the relapsed setting and identified 15 pts who discontinued acalabrutinib….to investigate the mutation evolution on acalabrutinib treatment, mutation profiles, particularly the mutation variant allelic fractions (VAFs), were compared between the baseline and progression samples from pt-1....mutation of MYCN, MEF2B, ATM, and NOTCH1 were identified in both tumors at similar VAFs, whereas mutation of CARD11 (two mutations), NLRC5 and B2M were detected only at progression.