Tipifarnib treatment results in inhibition of FTase and HDJ-2 protein farnesylation in PBMN cells from patients with multiple myeloma. PBMN cells were processed for (A) FTase activity assay or (B) SDS-PAGE Western immunoblotting with anti-HDJ-2 antibody as described in “Materials and methods.” B and T designate baseline pretreatment levels and levels during the 3rd week of tipifarnib treatment, respectively. U and P designate unprocessed and processed HDJ-2, respectively. Control baseline cpm values ranged from 2437 to 3218 for FTase activity levels.