Profiling of BCR signaling cascade in stereotyped subsets #1, #2, and #8. (A) Immunoblotting analysis of 3 representative responsive cases from stereotyped subsets #1, #2, and #8, in which BCR crosslinking increases p-PLCγ2 and p-ERK levels. (B) Densitometric analysis of p-ERK/ERK and p-PLCγ2/PLCγ2 levels in stereotyped subsets #1, #2, and #8 CLL samples after BCR crosslinking; the increase in p-PLCγ2 and p-ERK levels is more pronounced in subset #8 CLL cells. (C) Untreated subset #8 CLL cells exhibit low basal levels of p-ERK1/2 that increase after BCR engagement in vitro (+IgG), further documenting signaling capacity. *P < .05. CNTRL, unstimulated control.