BCR and B-cell chronic lymphocytic leukemia: Patients whose CLL B cells responded to IgM cross-linking with high BCR responsiveness required treatment after shorter periods of expectant monitoring (50% of cases treated by 12.4 months), compared to patients whose CLL B cells exhibited intermediate (healthy-like)-responsiveness (26.9 months) or low-responsiveness (36.3 months) (p<0.01).