Malignant CTCL cell lines selectively express Blk. (A) Descriptions and abbreviations (Abbr.) of the cell lines used in the study. (B) RT-PCR and (C,E,F) WB analyses of the expression of SFKs in the cell lines shown in panel A. (D) MF2000 cells were transiently transfected with nontargeting (NT) or Blk-specific siRNA, and the expression of Blk and Erk was determined by WB 48 hours after transfection.