Effects of tipifarnib on HDJ-2 protein farnesylation, Rap1 geranylgeranylation, and the levels of P-Akt/Akt, P-STAT3/STAT3, and P-Erk1/2/Erk1/2 and β-actin in bone marrow cells from patients with advanced multiple myeloma. Bone marrow cells were processed for Western immunoblotting and probed with antibodies against HDJ-2, Rap1, β-actin, and phosphorylated as well as total Akt, STAT3, and Erk1/2 as described in “Materials and methods.” β-Actin was used as loading control. B and T designate baseline and week 3 of treatment with tipifarnib, respectively. PD and SD designate progressive disease and stable disease, respectively.