RASGRP1/APTX is independent of the Bullinger prognostic classifier. (A) AML samples from 58 relapsed or refractory patients (including 4 patients with stable disease) were ordered according to hierarchic clustering using 93 probe sets that correspond to 75 of the 133 prognostic genes identified by Bullinger et al. Patients in cluster II are predicted to have a good prognosis. (B) Kaplan-Meier survival estimates of the hierarchic cluster–defined groups of patients. The median overall survival is 213 and 64 days for the good and poor prognostic subgroups, respectively. (C) The overall survival of the relapsed or refractory AML patient population stratified by the Bullinger CCP diagnostic classifier. The median overall survival is 128 and 73 days for the predicted good- and poor-prognosis patients, respectively. (D) The overall survival of patients stratified by both the Bullinger CCP prognostic classifier and the RASGRP1/APTX gene-expression ratio. “Double positive” patients are those who were predicted to both have a good prognosis and respond to tipifarnib. “Double negative” patients are those who are predicted to have a poor prognosis and be resistant to tipifarnib. “Positive/negative” patients are those who are predicted to either have a good prognosis and be resistant to tipifarnib or have a poor prognosis and respond to tipifarnib. The median overall survival was 182 days for “double positive” patients, 83 days for “positive/negative” patients, and 56 days for “double negative” patients, respectively (double positive vs positive/negative groups, P = .003; double negative vs positive/negative groups, P = .06).