No abstract

The inability to undergo apoptosis is a crucial mechanism of multidrug resistance in acute myeloid leukemia (AML), and the analysis of mitochondrial apoptotic proteins may represent a significant prognostic tool to predict outcome. Bcl-2 and Bax oncoproteins were evaluated in 255 de novo AML patients (pts) by flow cytometry using an anti-bcl-2 monoclonal antibody (MoAb) and an anti-bax MoAb. The results were expressed as an index (bax/bcl-2) obtained by dividing bax mean fluorescence intensity (MFI) and bcl-2 MFI. Lower bax/bcl-2 ratio was associated with French-American-British (FAB) M0-M1 classes (P ‫؍‬ .000 01) and CD34 more than 20% (P < .000 01). There were striking inverse correlations between CD34 or CD117 MFI and bax/bcl-2 values (r ‫؍‬ ؊.40, P < .000 001 and r ‫؍‬ ؊.29, P ‫؍‬ .000 002), confirming that immaturity is consistent with this index. Moreover, lower bax/bcl-2 levels were correlated with poor-risk cytogenetics (P ‫؍‬ .0002). A significant higher complete remission (CR) rate was found in pts with higher bax/bcl-2 levels (79% versus 45%; P ‫؍‬ .000 01). Also, both a longer overall survival (OS) and disease-free survival (DFS) were observed in pts with higher bax/bcl-2 levels (P ‫؍‬ .000 01 and ‫؍‬ .019). Noteworthy, bax/bcl-2 levels accurately predicted the clinical response and outcome of pts with normal or unknown cytogenetics. Indeed, within this subset of 147 pts, higher bax/bcl-2 ratio was significantly associated both with a higher CR rate (86% versus 42%; P < .000 01) and a longer OS (P ‫؍‬ .0016). The independent prognostic value of bax/bcl-2 ratio was confirmed in multivariate analysis. Therefore, mitochondrial oncoproteins, such as bcl-2 and bax, represent both sensitive indicators of clinical outcome and potential targets of novel proapoptotic molecules in order to circumvent chemoresistance. (Blood. 2003;

B-cell chronic lymphocytic leukemia (B-CLL) follows heterogeneous clinical courses, and several biological parameters need to be added to the current clinical staging systems to predict which patients will experience an indolent or an aggressive outcome. This study analyzed CD38 expression by flow cytometry and soluble APO1/Fas (sAPO1/Fas), Bcl-2 (sBcl-2), and CD23 (sCD23) proteins by immunoenzymatic methods to evaluate their effect on the clinical course of 168 unselected B-CLL patients. Intermediate/high risk modified Rai stages were characterized by a higher CD38 ؉ B-cell number (P ‫؍‬ .0002) and higher sCD23 levels (P < .0001). Moreover, CD38 ؉ B-cell percentages were significantly and directly associated both with ␤ 2 -microglobulin and sCD23 concentrations (P < .0001 and P ‫؍‬ .002, respectively). Both a higher tumor burden (lymphadenopathy/splenomegaly) and a lymphocyte doubling time less than 12 months were significantly associated with higher CD38 ؉ percentages (P < .0001 and P ‫؍‬ .0001, respectively). With regard to clinical outcome, progression-free survival was significantly longer (75% versus 37% at 5 years; P ‫؍‬ .00006) in patients with lower CD38 ؉ B-cell percentages. Furthermore, the risk of partial or no response to fludarabine increased with increasing CD38 expression (P ‫؍‬ .003), and a shorter overall survival (50% versus 92% at 8 years; P < .00001) characterized patients with more than 30% CD38 ؉ B-cell number. The predictive value of CD38 expression was maintained among the patients within the Rai intermediate risk group and was confirmed in multivariate analysis. Thus, the percentage of CD38 ؉ B cells appears to be an accurate predictor of clinical outcome and therefore could be used to indicate when more novel chemotherapeutic approaches are needed. , and CD19 and negative for surface CD22 and FMC7. 2 These cells overexpress the Bcl-2 gene product and are resistant to apoptosis; however, examining the relative levels of this antiapoptotic protein has not been particularly helpful in predicting clinical outcome. 3,4 The clinical course of patients with B-CLL can be quite variable, with many patients surviving for prolonged periods without any therapy, whereas others succumb rapidly despite aggressive treatment. 5 Although the 2 major staging systems have provided valuable information in addressing this clinical heterogeneity, 6,7 they have been unable to predict an indolent or aggressive course within the intermediate risk category. For this reason, several parameters such as lymphocyte doubling time (LDT), 8 serum levels of ␤ 2 -microglobulin, 9 soluble CD23 (sCD23), 10 serum thymidine kinase levels, 11 bone marrow histology, 12 and cytogenetic abnormalities 13 have been added to the current staging systems to differentiate prognostic subsets.Despite having several characteristics of naive B cells, such as sequences of V H genes in germline configuration (unmutated), B-CLL cells have been shown to have somatically mutated immunoglobulin variable region genes in at least half of the case...

We used flow cytometry to quantify minimal residual disease (MRD) in 56 patients with acute myeloid leukemia (AML) expressing a leukemia-associated phenotype. Thirty-four patients aged 18 to 60 years were entered into the AML-10 protocol (induction, consolidation, and autologous stem-cell transplantation [ASCT]), whereas 22 patients older than 60 years received the AML-13 protocol (induction, consolidation, and consolidation II). After induction, the level of MRD that was best associated with treatment outcome was 4.5 × 10−4 residual leukemic cells. However, the outcome in patients with at least 4.5 × 10−4 cells (n = 26) was not significantly different from that in patients with fewer leukemic cells (n = 30); there were 15 (58%) relapses in the first group and 12 (40%) relapses in the second. After consolidation, the most predictive MRD cutoff value was 3.5 × 10−4cells: 22 patients had an MRD level of 3.5 × 10−4 cells or higher and 17 (77%) of these patients had relapse, compared with 5 of 29 patients (17%) with lower MRD levels (P < .001). An MRD level of 3.5 × 10−4 cells or higher after consolidation was significantly correlated with poor or intermediate-risk cytogenetic findings, a multidrug resistance 1 (MDR1) phenotype, short duration of overall survival, and short duration of relapse-free survival (P = .014, .031, .00022, and .00014, respectively). In multivariate analysis, this MRD status was significantly associated with a high frequency of relapse (P < .001) and a short duration of overall (P = .025) and relapse-free survival (P = .007). ASCT did not alter the prognostic effect of high MRD levels after consolidation: the relapse rate after transplantation was 70%. Thus, we found that an MRD level of 3.5 × 10−4 cells or higher at the end of consolidation strongly predicts relapse and is significantly associated with an MDR1 phenotype and intermediate or unfavorable cytogenetic findings.