MAPK3 and B-cell chronic lymphocytic leukemia: Phosphorylation of the mitogen-activated protein kinase ERK (phospho-ERK1/2) was impaired in Jurkat T cells conjugated with CLL cells with p66Shc expression above threshold when compared to Jurkat T cells conjugated with healthy B cells (Figure 1C), with a significant further decrease in conjugates of Jurkat T cells with CLL cells with p66Shc expression below threshold (Figure 1C).