Silke Soucek

BAALC Expression and FLT3 Internal Tandem Duplication Mutations in Acute Myeloid Leukemia Patients With Normal Cytogenetics: Prognostic Implications

PURPOSE Evaluate the impact of BAALC (brain and acute leukemia, cytoplasmic), a gene whose expression has been associated with adverse outcome in acute myeloid leukemia (AML) with normal cytogenetics, and FLT3 internal tandem duplication (ITD) mutations as independent prognostic factors in a larger study. PATIENTS AND METHODS BAALC expression was determined by real-time reverse transcriptase polymerase chain reaction in pretreatment blood samples of 307 adults <or= 60 years of age with AML with normal cytogenetics. Patients were dichotomized at BAALCs median expression into low and high expressers. The FLT3 ITD mutant:wild-type ratio was determined by fragment analysis. RESULTS Compared with low-BAALC patients, high-BAALC patients had a higher rate of primary resistant leukemia (16% v 6%; P = .006). High BAALC expression was associated with a higher cumulative incidence of relapse (CIR; P = .018) and an inferior overall survival (OS; 3-year OS, 36% v 54%; P = .001). On multivariable analysis, high BAALC was independently predictive of resistant disease (P = .019), and high BAALC as well as a high FLT3 mutant:wild-type ratio were confirmed as the only factors predicting a high CIR (BAALC, P = .03; FLT3, P = .01) and inferior OS (BAALC, P = .001; FLT3, P = .012). CONCLUSION This study strengthens BAALC expression as one of the most important prognostic factors in AML patients with normal cytogenetics. BAALC expression and FLT3 mutation status should assist in tailoring induction and postremission therapies.

MDR1 and MRP1 gene expression are independent predictors for treatment outcome in adult acute myeloid leukaemia

Multi drug resistance (MDR) is a major obstacle for cancer therapy. The three major candidates accounting for the development of MDR in acute myeloid leukaemia (AML) are multi drug resistance gene (MDR1), multi drug resistance‐related protein gene (MRP1) and lung resistance protein gene (LRP). So far, the differential impact of resistance gene expression on treatment outcome in AML is not clear. Therefore, we examined MDR1, MRP1 and LRP gene expression at diagnosis in 331 adult AML patients in the context of other known prognostic factors, such as age, disease status, cytogenetics and FMS‐like tyrosine kinase 3 (FLT3)‐internal tandem duplication mutational status. Median observation time was longer than 5 years [64·1 months (40·0–87·6)]. MDR1 expression proved to be an independent prognostic factor for outcome of induction therapy (P < 0·001) and overall survival (P = 0·02), whereas MRP1 expression was an independent predictor for disease‐free survival (P = 0·01) in the multivariate analysis. This prognostic impact of both resistance genes was also found in patients with intermediate risk cytogenetics. LRP expression, however, had no impact on treatment outcome in AML. Our study shows that resistance gene expression should be considered together with age, cytogenetics and FLT3 mutational status for risk‐adapted treatment strategies in AML in the future.

Spleen enlargement in healthy donors during G–CSF mobilization of PBPCs

BACKGROUND: Recombinant human G–CSF is widely used to mobilize PBPCs in healthy donors for allogeneic transplantation. There have been concerns about donor safety because of splenic ruptures during G–CSF application. To address this problem, changes in splenic size in 91 healthy donors during G–CSF mobilization of allogeneic PBPCs were investigated.

The prognostic impact of 17p ( p53 ) deletion in 2272 adults with acute myeloid leukemia

Loss of p53—a tumor suppressor gene located on the short arm of chromosome 17 (band 17p13.1)—was detected in 105 out of 2272 (5%) adult acute myeloid leukemia (AML) patients who took part in the Study Alliance Leukemia AML96 and AML2003 multi center trials. There were 85 patients with 17p (p53) deletion with multiple aberrations and 20 patients with a 17p (p53) deletion as single aberration or with only one additional chromosomal abnormality. None of the p53-deleted patients displayed additional low-risk aberrations, like t(8;21) or inv(16). Significant positive association between p53 deletion and other high-risk factors was identified for del(5q) (P<0.001), −5 (P<0.001) and −7 (P<0.05). The molecular risk factors FLT3-ITD and NPM1 mutation showed an inverse correlation to the p53 deletion in complex aberrant patients (P<0.001). The multivariate analysis revealed p53 deletion without multiple aberrations as an independent negative prognostic factor for disease-free survival (P<0.001), relapse risk (P=0.028) and overall survival (P<0.001). Thus, the single p53 deletion should be considered as a high-risk aberration for future risk-adapted treatment strategies in AML.

Cytarabine Dose of 36 g/m2 Compared With 12 g/m2 Within First Consolidation in Acute Myeloid Leukemia: Results of Patients Enrolled Onto the Prospective Randomized AML96 Study

PURPOSE To assess the optimal cumulative dose of cytarabine for treatment of young adults with acute myeloid leukemia (AML) within a prospective multicenter treatment trial. PATIENTS AND METHODS Between 1996 and 2003, 933 patients (median age, 47 years; range 15 to 60 years) with untreated AML were randomly assigned at diagnosis to receive cytarabine within the first consolidation therapy at either a intermediate-dose of 12 g/m² (I-MAC) or a high-dose of 36 g/m² (H-MAC) combined with mitoxantrone. Autologous hematopoietic stem-cell transplantation or intermediate-dose cytarabine (10 g/m²) were offered as second consolidation. Patients with a matched donor could receive an allogeneic transplantation in a risk-adapted manner. RESULTS After double induction therapy including intermediate-dose cytarabine (10 g/m²), mitoxantrone, etoposide, and amsacrine, complete remission was achieved in 66% of patients. In the primary efficacy analysis population, a consolidation with either I-MAC or H-MAC did not result in significant differences in the 5-year overall (30% v 33%; P = .77) or disease-free survival (37% v 38%; P = .86) according to the intention-to-treat analysis. Besides a prolongation of neutropenia and higher transfusion demands in the H-MAC arm, rates of serious adverse events were comparable in the two groups. CONCLUSION In young adults with AML receiving intermediate-dose cytarabine induction, intensification of the cytarabine dose beyond 12 g/m² within first consolidation did not improve treatment outcome.

Immunophenotyping is an independent factor for risk stratification in AML

Chromosomal abnormalities are one of the most important prognostic factors in acute myeloid leukemia (AML). However, only a limited number of patients have such informative chromosomal abnormalities. The prognostic value of immunophenotyping in this disease is still unclear.

Cup-like acute myeloid leukemia: new disease or artificial phenomenon?

In acute myeloid leukemia, cup-like nuclear morphology is an indicator of normal karyotype. We investigated cup-like nuclear morphology of acute myeloid leukemia blasts in 266 randomly selected patients and its association with hematologic findings, disease markers and outcome data. Cup-like acute myeloid leukemia was diagnosed in 55 patients (21%). It was associated with female sex, high white blood cell and blast cell counts, normal karyotype, and low CD34 and HLA-DR expression. Mutations of FLT3, NPM1 or both were detected in 84.9% compared with 58.1% in cases without this morphology (p=0.001). There was no influence on response to treatment or survival. Therefore, cup-like nuclear morphology is an indicator of normal karyotype and should guide more specific molecular analyses.

A sensitive model for prediction of relapse in adult acute myeloid leukaemia with t(8;21) using white blood cell count, CD56 and MDR1 gene expression at diagnosis

Acute myeloid leukaemia (AML) carrying t(8;21) has an overall favourable prognosis. However, relapse occurs and the impact of multidrug resistance gene (MDR1) expression on recurring disease in this group of patients is not known. We determined quantifiable MDR1 expression in the bone marrow of 28 AML patients with t(8;21) by a validated real‐time polymerase chain reaction assay. Using MDR1 expression, white blood cell count and CD56 expression at diagnosis we observed complete concordance of predicted and observed relapses. A calculated logit out of these three variables was a strong independent prognostic factor for overall (P = 0·007) and disease‐free survival (P = 0·002).

Risk stratification using a new prognostic score for patients with secondary acute myeloid leukemia: results of the prospective AML96 trial

Patients with secondary acute myeloid leukemia (sAML) are generally thought to have a poor prognosis. As there are no prognostic risk stratification models for patients with sAML available, the aim of this study was to obtain a scoring system. Prognostic factors influencing overall survival (OS) and event-free survival (EFS) were analyzed in 305 sAML patients treated in the prospective AML96 trial. The obtained prognostic scoring system was then validated in an independent patient cohort included in the AML2003 and AML60+ trials. In addition to the known risk factors for AML, age and karyotype, we identified the absolute platelet count and the Nucleophosmin 1 mutational status at diagnosis as prognostic factors of sAML patients. A pronounced distribution of sAML patients into three score groups was achieved showing a 2-year OS/EFS of 52/44% for patients in the low-risk group, 21/12% in the intermediate-risk group and 7/3% in the high-risk group (both P<0.001). Validation of this scoring system in a second independent set of sAML patients revealed similar significantly different survival results. In conclusion, for the first time, a prognostic scoring system is provided for sAML patients, allowing differential treatment strategies in the future.

Intratumoral heterogeneity and TERT promoter mutations in progressive/higher-grade meningiomas

Background Recent studies have reported mutations in the telomerase reverse transcriptase promoter (TERTp) in meningiomas. We sought to determine the frequency, clonality and clinical significance of telomere gene alterations in a cohort of patients with progressive/higher-grade meningiomas. Methods We characterized 64 temporally- and regionally-distinct specimens from 26 WHO grade III meningioma patients. On initial diagnoses, the meningiomas spanned all WHO grades (3 grade I, 13 grade II and 10 grade III). The tumor samples were screened for TERTp and ATRX/DAXX mutations, and TERT rearrangements. Additionally, TERTp was sequenced in a separate cohort of 19 patients with radiation-associated meningiomas. We examined the impact of mutational status on patients’ progression and overall survival. Results Somatic TERTp mutations were detected in six patients (6/26 = 23%). Regional intratumoral heterogeneity in TERTp mutation status was noted. In 4 patients, TERTp mutations were detected in recurrent specimens but not in the available specimens of the first surgery. Additionally, a TERT gene fusion (LPCAT1-TERT) was found in one sample. In contrary, none of the investigated samples harbored an ATRX or DAXX mutation. In the cohort of radiation-induced meningiomas, TERTp mutation was detected in two patients (10.5%). Importantly, we found that patients with emergence of TERTp mutations had a substantially shorter OS than their TERTp wild-type counterparts (2.7 years, 95% CI 0.9 – 4.5 years versus 10.8 years, 95% CI 7.8 -12.8 years, p=0.003). Conclusions In progressive/higher-grade meningiomas,TERTp mutations are associated with poor survival, supporting a model in which selection of this alteration is a harbinger of aggressive tumor development. In addition, we observe spatial intratumoral heterogeneity of TERTp mutation status, consistent with this model of late emergence in tumor evolution. Thus, early detection of TERTp mutations may define patients with more aggressive meningiomas. Stratification for TERT alterations should be adopted in future clinical trials of progressive/higher-grade meningiomas.