Association of sIgM-mediated signal responses with CD38, ZAP-70, and sIgM expression in subsets of U-CLL and M-CLL. Cases (107) with signaling responses above (S) or below (N) the cutoff of 5% response were analyzed for expression of (A) CD38, (C) ZAP-70, or (E) sIgM by flow cytometry. Superimposition of mutational status (U or M) was then used to assess differential expression of (B) CD38, (D) ZAP-70, or (F) sIgM in responders or nonresponders within U-CLL or M-CLL. Horizontal bars indicate median values. Statistical analysis was done using the Mann-Whitney test (2-tailed, 95%CI). The dotted lines show the cutoff values, 30% and 20%, respectively, used to define (A-B) CD38 and (C-D) ZAP-70 status.