MAF screening in follow-up patients. (A) Sequential samples from patients at progression, follow-up visits and PR/VGPR. (B₁) Patients who have progressed from aWM or IgM-MGUS the median MAF of MYD88^L265P was increased while in follow-up aWM patients the median MAF was decreased. (B₂) In sWM patients with progressive disease (PD), the median MAF was increased while in sWM patients with stable disease (SD) or PR/VGPR the median MAF was decreased.