Effect of SETBP1 on cell proliferation and PP2A activity. (A) MTS assays showing the effect of ectopic SETBP1 expression alone or with SET-specific siRNAs on the growth of HEL and 32Dcl3. (B) PP2A phosphatase assay in HEL and 32Dcl3 cells either not transfected or expressing the empty vector as a control, SETBP1 alone, or SETBP1 with SET down-regulated by SET-specific siRNAs.