Analysis of anti-IgM–induced ERK1/2 phosphorylation. (A) Immunoblot analysis of ERK1/2 phosphorylation in a representative CLL sample stimulated with anti-IgM (n = 12). (B) Correlations between maximum anti-IgM–induced phosphorylation of BIM_EL and BIM_L and phospho-ERK1/2 signaling responses as measured by flow cytometry. A 1.2-fold cutoff (compared with unstimulated cells) was used to assign cases P-ERK1/2–negative or –positive. (C) Correlation between fold increase in ERK1/2 phosphorylation (measured by flow cytometry) and intracellular Ca²⁺ responses. (D) Correlation between fold increase in ERK1/2 phosphorylation (measured by flow cytometry) and stable/progressive disease. Graphs show individual data points as well as means (horizontal line) and the statistical significance of any differences (Mann-Whitney test). Differences that reached statistical significance (P < .05) are boxed.