SOCS3 and B-cell chronic lymphocytic leukemia: We did not observe an up-regulation of SOCS3 in the B cell leukemia cell lines investigated (697, Mec1) with the exception of the OSU-CLL cell line (derived from CLL patient B cells) recently described by our group [18] (Supplemental Figure 1), indicating that this mechanism may be specific to the primary CLL B cells.