Chromosomal instability in aneuploid acute lymphoblastic leukemia associates with disease progression

Chromosomal instability (CIN) lies at the core of cancer development leading to aneuploidy, chromosomal copy-number heterogeneity (chr-CNH) and ultimately, unfavorable clinical outcomes. Despite its ubiquity in cancer, the presence of CIN in childhood B-cell acute lymphoblastic leukemia (cB-ALL), the most frequent pediatric cancer showing high frequencies of aneuploidy, remains unknown. Here, we elucidate the presence of CIN in aneuploid cB-ALL subtypes using single-cell whole-genome sequencing of primary cB-ALL samples and by generating and functionally characterizing patient-derived xenograft models (cB-ALL-PDX). We report higher rates of CIN across aneuploid than in euploid cB-ALL that strongly correlate with intraclonal chr-CNH and overall survival in mice. This association was further supported by in silico mathematical modeling. Moreover, mass-spectrometry analyses of cB-ALL-PDX revealed a "CIN signature" enriched in mitotic-spindle regulatory pathways, which was confirmed by RNA-sequencing of a large cohort of cB-ALL samples. The link between the presence of CIN in aneuploid cB-ALL and disease progression opens new possibilities for patient stratification and offers a promising new avenue as a therapeutic target in cB-ALL treatment.

The relapsed acute lymphoblastic leukemia network (ReALLNet): a multidisciplinary project from the spanish society of pediatric hematology and oncology (SEHOP)

Acute lymphoblastic leukemia (ALL) is the most common pediatric cancer, with survival rates exceeding 85%. However, 15% of patients will relapse; consequently, their survival rates decrease to below 50%. Therefore, several research and innovation studies are focusing on pediatric relapsed or refractory ALL (R/R ALL). Driven by this context and following the European strategic plan to implement precision medicine equitably, the Relapsed ALL Network (ReALLNet) was launched under the umbrella of SEHOP in 2021, aiming to connect bedside patient care with expert groups in R/R ALL in an interdisciplinary and multicentric network. To achieve this objective, a board consisting of experts in diagnosis, management, preclinical research, and clinical trials has been established. The requirements of treatment centers have been evaluated, and the available oncogenomic and functional study resources have been assessed and organized. A shipping platform has been developed to process samples requiring study derivation, and an integrated diagnostic committee has been established to report results. These biological data, as well as patient outcomes, are collected in a national registry. Additionally, samples from all patients are stored in a biobank. This comprehensive repository of data and samples is expected to foster an environment where preclinical researchers and data scientists can seek to meet the complex needs of this challenging population. This proof of concept aims to demonstrate that a network-based organization, such as that embodied by ReALLNet, provides the ideal niche for the equitable and efficient implementation of "what's next" in the management of children with R/R ALL.

Fusion InPipe, an integrative pipeline for gene fusion detection from RNA-seq data in acute pediatric leukemia

RNA sequencing (RNA-seq) is a reliable tool for detecting gene fusions in acute leukemia. Multiple bioinformatics pipelines have been developed to analyze RNA-seq data, but an agreed gold standard has not been established. This study aimed to compare the applicability of 5 fusion calling pipelines (Arriba, deFuse, CICERO, FusionCatcher, and STAR-Fusion), as well as to define and develop an integrative bioinformatics pipeline (Fusion InPipe) to detect clinically relevant gene fusions in acute pediatric leukemia. We analyzed RNA-seq data by each pipeline individually and by Fusion InPipe. Each algorithm individually called most of the fusions with similar sensitivity and precision. However, not all rearrangements were called, suggesting that choosing a single pipeline might cause missing important fusions. To improve this, we integrated the results of the five algorithms in just one pipeline, Fusion InPipe, comparing the output from the agreement of 5/5, 4/5, and 3/5 algorithms. The maximum sensitivity was achieved with the agreement of 3/5 algorithms, with a global sensitivity of 95%, achieving a 100% in patients' data. Furthermore, we showed the necessity of filtering steps to reduce the false positive detection rate. Here, we demonstrate that Fusion InPipe is an excellent tool for fusion detection in pediatric acute leukemia with the best performance when selecting those fusions called by at least 3/5 pipelines.

A miRNA signature related to stemness identifies high-risk patients in paediatric acute myeloid leukaemia

Clinical and biological variables like genetic aberrations at diagnosis and the levels of measurable residual disease (MRD) are the most powerful biomarkers to predict the outcome of paediatric leukaemia. Recently, a model integrating the genetic abnormalities, transcriptional identity, and leukaemia stemness measured as leukaemic stem cell score (pLSC6) has been proposed to identify high-risk paediatric acute myeloid leukaemia (AML) patients. However, the role of epigenetics in defining prognosis still needs to be established. We evaluated the role of 89 miRNAs regulating stemness and their contribution to predicting outcomes in 110 paediatric patients with acute leukaemia. We identified a 24-miRNA signature capable of distinguishing paediatric AML patients with excellent or poor outcomes. We validated these results in an independent cohort using public repository-based data. The 24-miRNA signature was significantly associated with the leukaemic stemness scores and the underlying genetics of patients. Notably, the combination of classical prognostic factors (MRD and genetics), the pLSC6 score and the 24-miRNA signature had a higher capacity to predict the overall and event-free survival than each variable individually. Our 24-miRNA signature provides epigenetic data to integrate into genetics, MRD and stemness-related leukaemic scores to refine risk stratification in paediatric AML patients.

TIM3, a human acute myeloid leukemia stem cell marker, does not enrich for leukemia-initiating stem cells in B-cell acute lymphoblastic leukemia

Not available.

Low input capture Hi-C (liCHi-C) identifies promoter-enhancer interactions at high-resolution

Long-range interactions between regulatory elements and promoters are key in gene transcriptional control; however, their study requires large amounts of starting material, which is not compatible with clinical scenarios nor the study of rare cell populations. Here we introduce low input capture Hi-C (liCHi-C) as a cost-effective, flexible method to map and robustly compare promoter interactomes at high resolution. As proof of its broad applicability, we implement liCHi-C to study normal and malignant human hematopoietic hierarchy in clinical samples. We demonstrate that the dynamic promoter architecture identifies developmental trajectories and orchestrates transcriptional transitions during cell-state commitment. Moreover, liCHi-C enables the identification of disease-relevant cell types, genes and pathways potentially deregulated by non-coding alterations at distal regulatory elements. Finally, we show that liCHi-C can be harnessed to uncover genome-wide structural variants, resolve their breakpoints and infer their pathogenic effects. Collectively, our optimized liCHi-C method expands the study of 3D chromatin organization to unique, low-abundance cell populations, and offers an opportunity to uncover factors and regulatory networks involved in disease pathogenesis.

β-Catenin activity induces an RNA biosynthesis program promoting therapy resistance in T-cell acute lymphoblastic leukemia

Understanding the molecular mechanisms that contribute to the appearance of chemotherapy resistant cell populations is necessary to improve cancer treatment. We have now investigated the role of β-catenin/CTNNB1 in the evolution of T-cell Acute Lymphoblastic Leukemia (T-ALL) patients and its involvement in therapy resistance. We have identified a specific gene signature that is directly regulated by β-catenin, TCF/LEF factors and ZBTB33/Kaiso in T-ALL cell lines, which is highly and significantly represented in five out of six refractory patients from a cohort of 40 children with T-ALL. By subsequent refinement of this gene signature, we found that a subset of β-catenin target genes involved with RNA-processing function are sufficient to segregate T-ALL refractory patients in three independent cohorts. We demonstrate the implication of β-catenin in RNA and protein synthesis in T-ALL and provide in vitro and in vivo experimental evidence that β-catenin is crucial for the cellular response to chemotherapy, mainly in the cellular recovery phase after treatment. We propose that combination treatments involving chemotherapy plus β-catenin inhibitors will enhance chemotherapy response and prevent disease relapse in T-ALL patients.

Clonal heterogeneity and rates of specific chromosome gains are risk predictors in childhood high-hyperdiploid B-cell acute lymphoblastic leukemia

B‐cell acute lymphoblastic leukemia (B‐ALL) is the commonest childhood cancer. High hyperdiploidy (HHD) identifies the most frequent cytogenetic subgroup in childhood B‐ALL. Although hyperdiploidy represents an important prognostic factor in childhood B‐ALL, the specific chromosome gains with prognostic value in HHD‐B‐ALL remain controversial, and the current knowledge about the hierarchy of chromosome gains, clonal heterogeneity and chromosomal instability in HHD‐B‐ALL remains very limited. We applied automated sequential‐iFISH coupled with single‐cell computational modeling to identify the specific chromosomal gains of the eight typically gained chromosomes in a large cohort of 72 primary diagnostic (DX, n = 62) and matched relapse (REL, n = 10) samples from HHD‐B‐ALL patients with either favorable or unfavorable clinical outcome in order to characterize the clonal heterogeneity, specific chromosome gains and clonal evolution. Our data show a high degree of clonal heterogeneity and a hierarchical order of chromosome gains in DX samples of HHD‐B‐ALL. The rates of specific chromosome gains and clonal heterogeneity found in DX samples differ between HHD‐B‐ALL patients with favorable or unfavorable clinical outcome. In fact, our comprehensive analyses at DX using a computationally defined risk predictor revealed low levels of trisomies +18+10 and low levels of clonal heterogeneity as robust relapse risk factors in minimal residual disease (MRD)‐negative childhood HHD‐B‐ALL patients: relapse‐free survival beyond 5 years: 22.1% versus 87.9%, P < 0.0001 and 33.3% versus 80%, P < 0.0001, respectively. Moreover, longitudinal analysis of matched DX‐REL HHD‐B‐ALL samples revealed distinct patterns of clonal evolution at relapse. Our study offers a reliable prognostic sub‐stratification of pediatric MRD‐negative HHD‐B‐ALL patients.

Technical Validation and Clinical Utility of an NGS Targeted Panel to Improve Molecular Characterization of Pediatric Acute Leukemia

Development of next-generation sequencing (NGS) has provided useful genetic information to redefine diagnostic, prognostic, and therapeutic strategies for the management of acute leukemia (AL). However, the application in the clinical setting is still challenging. Our aim was to validate the AmpliSeq™ for Illumina® Childhood Cancer Panel, a pediatric pan-cancer targeted NGS panel that includes the most common genes associated with childhood cancer, and assess its utility in the daily routine of AL diagnostics. In terms of sequencing metrics, the assay reached all the expected values. We obtained a mean read depth greater than 1000×. The panel demonstrated a high sensitivity for DNA (98.5% for variants with 5% variant allele frequency (VAF)) and RNA (94.4%), 100% of specificity and reproducibility for DNA and 89% of reproducibility for RNA. Regarding clinical utility, 49% of mutations and 97% of the fusions identified were demonstrated to have clinical impact. Forty-one percent of mutations refined diagnosis, while 49% of them were considered targetable. Regarding RNA, fusion genes were more clinically impactful in terms of refining diagnostic (97%). Overall, the panel found clinically relevant results in the 43% of patients tested in this cohort. To sum up, we validated a reliable and reproducible method to refine pediatric AL diagnosis, prognosis, and treatment, and demonstrated the feasibility of incorporating a targeted NGS panel into pediatric hematology practice.

Clonal dynamics in pediatric B-cell precursor acute lymphoblastic leukemia with very early relapse

INTRODUCTION

One-quarter of the relapses in children with B-cell precursor acute lymphoblastic leukemia (BCP-ALL) occur very early (within 18 months, before completion of treatment), and prognosis in these patients is worse compared to cases that relapse after treatment has ended.

METHODS

In this study, we performed a genomic analysis of diagnosis-relapse pairs of 12 children who relapsed very early, followed by a deep-sequencing validation of all identified mutations. In addition, we included one case with a good initial treatment response and on-treatment relapse at the end of upfront therapy.

RESULTS

We observed a dynamic clonal evolution in all cases, with relapse almost exclusively originating from a subclone at diagnosis. We identified several driver mutations that may have influenced the outgrowth of a minor clone at diagnosis to become the major clone at relapse. For example, a minimal residual disease (MRD)-based standard-risk patient with ETV6-RUNX1-positive leukemia developed a relapse from a TP53-mutated subclone after loss of the wildtype allele. Furthermore, two patients with TCF3-PBX1-positive leukemia that developed a very early relapse carried E1099K WHSC1 mutations at diagnosis, a hotspot mutation that was recurrently encountered in other very early TCF3-PBX1-positive leukemia relapses as well. In addition to alterations in known relapse drivers, we found two cases with truncating mutations in the cohesin gene RAD21.

CONCLUSION

Comprehensive genomic characterization of diagnosis-relapse pairs shows that very early relapses in BCP-ALL frequently arise from minor subclones at diagnosis. A detailed understanding of the therapeutic pressure driving these events may aid the development of improved therapies.

Lower incidence of clinical allergy with PEG-asparaginase upfront versus the sequential use of native E. coli asparaginase followed by PEG-ASP in pediatric patients with acute lymphoblastic leukemia

Asparaginase (ASP) is an essential component for the acute lymphoblastic leukemia (ALL) treatment, but toxicities, such as allergy, frequently limit its use. Although the potentially lower PEG-ASP formulation immunogenicity, few studies with conflicting results have compared the allergy incidence between Escherichia coli-ASP and PEG-ASP in the same protocol. We aimed at comparing the allergy incidence in children receiving native E. coli-ASP versus PEG-ASP within the same clinical protocol (Spanish Society of Pediatric Hematology and Oncology ALL-SEHOP-PETHEMA 2013). One hundred and twenty-six children (1-19 years) diagnosed with ALL from 2013 to 2020 were included. Patients in group 1 received a sequential scheme of native E. coli-ASP 10,000 IU/m² intramuscularly (IM) followed by PEG-ASP 1000 IU/m² IM. Patients in group 2 received PEG-ASP 1000 IU/m² IM upfront. Clinical allergy incidence was compared between both groups. Serum ASP activity (SAA) was measured in a subgroup of patients, and silent inactivation was recorded. The cumulative incidence of clinical allergy was significantly higher in group 1 (native followed by PEG-ASP) than in group 2 (PEG-ASP upfront), 24.7% versus 4.1% (p = 0.0085). Adequate ASP activity was achieved with PEG-ASP 1000 IU/m² dose in most patients (median SAA 412.5 and 453.0 IU/L at days 7 and 14). The incidence of silent inactivation in PEG-ASP upfront patients was very low. PEG-ASP-used upfront was associated with a lower incidence of clinical allergy than that observed in the sequential use of native E. coli-ASP followed by PEG-ASP. PEG-ASP at 1000 IU/m² was effective in achieving enough ASP activity in most patients.

LncRNA-mRNA Co-Expression Analysis Identifies AL133346.1/CCN2 as Biomarkers in Pediatric B-Cell Acute Lymphoblastic Leukemia

Simple Summary

Dysregulation of noncoding RNAs has been described in numerous types of cancers and it has been associated with oncogenic or tumor suppressor activities. However, the signature of clinically relevant noncoding RNAs in pediatric B-cell acute lymphoblastic leukemia is still poorly understood. In a search for long non-coding RNAs that characterize pediatric B-cell acute lymphoblastic leukemia, we found that the long non-coding RNA AL133346.1 and a neighbouring protein-coding mRNA (CCN2) were significantly over-expressed in leukemia samples compared to healthy bone marrow. Survival analysis showed that patients with high CCN2 expression had a significantly better prognosis. These data suggest that AL133346.1/CCN2 could be useful for discriminating subtypes of leukemia and that CCN2 expression could predict the prognosis of pediatric patients with B-cell acute lymphoblastic leukemia.

Abstract

Pediatric acute B-cell lymphoblastic leukemia (B-ALL) constitutes a heterogeneous and aggressive neoplasia in which new targeted therapies are required. Long non-coding RNAs have recently emerged as promising disease-specific biomarkers for the clinic. Here, we identified pediatric B-ALL-specific lncRNAs and associated mRNAs by comparing the transcriptomic signatures of tumoral and non-tumoral samples. We identified 48 lncRNAs that were differentially expressed between pediatric B-ALL and healthy bone marrow samples. The most relevant lncRNA/mRNA pair was AL133346.1/CCN2 (previously known as RP11-69I8.3/CTGF), whose expression was positively correlated and increased in B-ALL samples. Their differential expression pattern and their strong correlation were validated in external B-ALL datasets (Therapeutically Applicable Research to Generate Effective Treatments, Cancer Cell Line Encyclopedia). Survival curve analysis demonstrated that patients with “high” expression levels of CCN2 had higher overall survival than those with “low” levels (p = 0.042), and this gene might be an independent prognostic biomarker in pediatric B-ALL. These findings provide one of the first detailed descriptions of lncRNA expression profiles in pediatric B-ALL and indicate that these potential biomarkers could help in the classification of leukemia subtypes and that CCN2 expression could predict the survival outcome of pediatric B-cell acute lymphoblastic leukemia patients.

Measurable Residual Disease Assessed by Flow-Cytometry Is a Stable Prognostic Factor for Pediatric T-Cell Acute Lymphoblastic Leukemia in Consecutive SEHOP Protocols Whereas the Impact of Oncogenetics Depends on Treatment

Robust and applicable risk-stratifying genetic factors at diagnosis in pediatric T-cell acute lymphoblastic leukemia (T-ALL) are still lacking, and most protocols rely on measurable residual disease (MRD) assessment. In our study, we aimed to analyze the impact of NOTCH1, FBXW7, PTEN, and RAS mutations, the measurable residual disease (MRD) levels assessed by flow cytometry (FCM-MRD) and other reported risk factors in a Spanish cohort of pediatric T-ALL patients. We included 199 patients treated with SEHOP and PETHEMA consecutive protocols from 1998 to 2019. We observed a better outcome of patients included in the newest SEHOP-PETHEMA-2013 protocol compared to the previous SHOP-2005 cohort. FCM-MRD significantly predicted outcome in both protocols, but the impact at early and late time points differed between protocols. The impact of FCM-MRD at late time points was more evident in SEHOP-PETHEMA 2013, whereas in SHOP-2005 FCM-MRD was predictive of outcome at early time points. Genetics impact was different in SHOP-2005 and SEHOP-PETHEMA-2013 cohorts: NOTCH1 mutations impacted on overall survival only in the SEHOP-PETHEMA-2013 cohort, whereas homozygous deletions of CDKN2A/B had a significantly higher CIR in SHOP-2005 patients. We applied the clinical classification combining oncogenetics, WBC count and MRD levels at the end of induction as previously reported by the FRALLE group. Using this score, we identified different subgroups of patients with statistically different outcome in both Spanish cohorts. In SHOP-2005, the FRALLE classifier identified a subgroup of high-risk patients with poorer survival. In the newest protocol SEHOP-PETHEMA-2013, a very low-risk group of patients with excellent outcome and no relapses was detected, with borderline significance. Overall, FCM-MRD, WBC count and oncogenetics may refine the risk-stratification, helping to design tailored approaches for pediatric T-ALL patients.

FMS-like tyrosine kinase 3 (FLT3) modulates key enzymes of nucleotide metabolism implicated in cytarabine responsiveness in pediatric acute leukemia

Treatment of pediatric acute leukemia might involve combined therapies targeting the FMS-like tyrosine kinase 3 (FLT3) receptor (i.e. quizartinib - AC220) and nucleotide metabolism (cytarabine - AraC). This study addressed the possibility of FLT3 modulating nucleoside salvage processes and, eventually, cytarabine action. Bone marrow samples from 108 pediatric leukemia patients (B-cell precursor acute lymphoblastic leukemia, BCP-ALL: 83; T-ALL: 9; acute myeloid leukemia, AML: 16) were used to determine the mRNA expression levels of FLT3, the cytarabine activating kinase dCK, and the nucleotidases cN-II and SAMHD1. FLT3 mRNA levels positively correlated with dCK, cN-II and SAMHD1 in the studied cohort. FLT3 inhibition using AC220 promoted the expression of cN-II in MV4-11 cells. Indeed, inhibition of cN-II with anthraquinone-2,6-disulfonic acid (AdiS) further potentiated the synergistic action of AC220 and cytarabine, at low concentrations of this nucleoside analog. FLT3 inhibition also down-regulated phosphorylated forms of SAMHD1 in MV4-11 and SEM cells. Thus, inhibition of FLT3 may also target the biochemical machinery associated with nucleoside salvage, which may modulate the ability of nucleoside-derived drugs. In summary, this contribution highlights the need to expand current knowledge on the mechanistic events linking tyrosine-kinase receptors, likely to be druggable in cancer treatment, and nucleotide metabolism, particularly considering tumor cells undergo profound metabolic reprogramming.

A 4-gene expression prognostic signature might guide post-remission therapy in patients with intermediate-risk cytogenetic acute myeloid leukemia

In intermediate-risk cytogenetic acute myeloid leukemia (IRC-AML) patients, novel biomarkers to guide post-remission therapy are needed. We analyzed with high-density arrays 40 IRC-AML patients who received a non-allogeneic hematopoietic stem-cell transplantation-based post-remission therapy, and identified a signature that correlated with early relapse. Subsequently, we analyzed selected 187 genes in 49 additional IRC-AML patients by RT-PCR. BAALC, MN1, SPARC and HOPX overexpression correlated to refractoriness. BAALC or ALDH2 overexpression correlated to shorter overall survival (OS) (5-year OS: 33 ± 8.6% vs. 73.7 ± 10.1%, p = .006; 32 ± 9.3% vs. 66.4 ± 9.7%, p = .016), whereas GPR44 or TP53INP1 overexpression correlated to longer survival (5-year OS: 66.7 ± 10.3% vs. 35.4 ± 9.1%, p = .04; 58.3 ± 8.2% vs. 23.1 ± 11.7%, p = .029). A risk-score combining these four genes expression distinguished low-risk and high-risk patients (5-year OS: 79 ± 9% vs. 30 ± 8%, respectively; p = .001) in our cohort and in an independent set of patients from a public repository. Our 4-gene signature may add prognostic information and guide post-remission treatment in IRC-AML patients.

A Paradoxical Tumor-Suppressor Role for the Rac1 Exchange Factor Vav1 in T Cell Acute Lymphoblastic Leukemia

Rho guanine exchange factors (GEFs), the enzymes that stimulate Rho GTPases, are deemed as potential therapeutic targets owing to their protumorigenic functions. However, the understanding of the spectrum of their pathobiological roles in tumors is still very limited. We report here that the GEF Vav1 unexpectedly possesses tumor-suppressor functions in immature T cells. This function entails the noncatalytic nucleation of complexes between the ubiquitin ligase Cbl-b and the intracellular domain of Notch1 (ICN1) that favors ICN1 ubiquitinylation and degradation. Ablation of Vav1 promotes ICN1 signaling and the development of T cell acute lymphoblastic leukemia (T-ALL). The downregulation of Vav1 is essential for the pathogenesis of human T-ALL of the TLX⁺ clinical subtype, further underscoring the suppressor role of this pathway.

FLT3 is implicated in cytarabine transport by human equilibrative nucleoside transporter 1 in pediatric acute leukemia

FLT3 abnormalities are negative prognostic markers in acute leukemia. Infant leukemias are a subgroup with frequent MLL (KMT2A) rearrangements, FLT3 overexpression and high sensitivity to cytarabine, but dismal prognosis. Cytarabine is transported into cells by Human Equilibrative Nucleoside Transporter-1 (hENT1, SLC29A1), but the mechanisms that regulate hENT1 in acute leukemia have been scarcely studied.We explored the expression and functional link between FLT3 and main cytarabine transporters in 50 pediatric patients diagnosed with acute lymphoblastic leukemia and MLL rearrangement (ALL-MLL+) and other subtypes of leukemia, and in leukemia cell lines.A significant positive correlation was found between FLT3 and hENT1 expression in patients. Cytarabine uptake into cells was mediated mainly by hENT1, hENT2 and hCNT1. hENT1-mediated uptake of cytarabine was transiently abolished by the FLT3 inhibitor PKC412, and this effect was associated with decreased hENT1 mRNA and protein levels. Noticeably, the cytotoxicity of cytarabine was lower when cells were first exposed to FLT3 inhibitors (PKC412 or AC220), probably due to decreased hENT1 activity, but we observed a higher cytotoxic effect if FLT3 inhibitors were administered after cytarabine.FLT3 regulates hENT1 activity and thereby affects cytarabine cytotoxicity. The sequence of administration of cytarabine and FLT3 inhibitors is important to maintain their efficacy.

Outcome and toxicities associated to chemotherapy in children with acute lymphoblastic leukemia and Gilbert syndrome. Usefulness of UGT1A1 mutational screening

BACKGROUND

Acute lymphoblastic leukemia (ALL) is the most frequent cancer in childhood. Although intensive chemotherapy has improved survival in those patients, important side effects, including hyperbilirubinemia, are frequent. Gilbert syndrome (GS) is a frequent condition that causes a reduction in glucuronidation and intermittent hyperbilirubinemia episodes. This could provoke a greater exposure to some cytotoxic agents used in ALL, increasing the risk of toxicity. On the other hand, unexplained hyperbilirubinemia could lead to unnecessary modifications or even treatment withdrawals, which could increase the risk of relapse, but data regarding this in ALL pediatric population are scarce.

METHODS

Retrospective study to analyze toxicity, outcome and treatment modifications related to GS in children diagnosed with ALL.

RESULTS

A total of 23 of 159 patients were diagnosed with GS. They had statistically higher hyperbilirubinemias during all treatment phases (P < 0.0001) and a slower methotrexate clearance when it was administered during a 24-hr infusion at high doses (patients with GS: 74 hr ± 19 vs. patients without GS: 64 hr ± 8; P <  .002). However, no relevant toxicity or delays in treatment were found in them. Finally, changes in treatment due to hyperbilirubinemia were only done in 5 patients with GS.

CONCLUSIONS

Differences in outcome were not found in patients with GS. Universal screening for GS appears to be not necessary in pediatric patients with ALL. However, when hyperbilirubinemia is observed, it must be rule out in order to avoid unnecessary changes in treatment.

The transcriptional repressor HDAC7 promotes apoptosis and c-Myc downregulation in particular types of leukemia and lymphoma

The generation of B cells is a complex process requiring several cellular transitions, including cell commitment and differentiation. Proper transcriptional control to establish the genetic programs characteristic of each cellular stage is essential for the correct development of B lymphocytes. Deregulation of these particular transcriptional programs may result in a block in B-cell maturation, contributing to the development of hematological malignancies such as leukemia and lymphoma. However, very little is currently known about the role of transcriptional repressors in normal and aberrant B lymphopoiesis. Here we report that histone deacetylase 7 (HDAC7) is underexpressed in pro-B acute lymphoblastic leukemia (pro-B-ALL) and Burkitt lymphoma. Ectopic expression of HDAC7 induces apoptosis, leads to the downregulation of c-Myc and inhibits the oncogenic potential of cells in vivo, in a xenograft model. Most significantly, we have observed low levels of HDAC7 expression in B-ALL patient samples, which is correlated with the increased levels of c-Myc. From a mechanistic angle, we show that ectopically expressed HDAC7 localizes to the nucleus and interacts with the transcription factor myocyte enhancer factor C (MEF2C) and the corepressors HDAC3 and SMRT. Accordingly, both the HDAC7–MEF2C interaction domain as well as its catalytic domain are involved in the reduced cell viability induced by HDAC7. We conclude that HDAC7 has a potent anti-oncogenic effect on specific B-cell malignancies, indicating that its deregulation may contribute to the pathogenesis of the disease.

Multiplex real-time PCR for prompt diagnosis of an outbreak of human parainfluenza 3 virus in children with acute leukemia

Introduction

Human parainfluenza virus type 3 (HPIV-3) causes significant morbimortality in immunocompromised patients. Outbreaks of severe pneumonitis have been previously described in this setting.

Materials and methods

Retrospective observational study in children diagnosed with acute leukemia and a documented HPIV-3 infection in the context of a nosocomial outbreak occurred in a single center.

Result

During summer 2012, an HPIV-3 infection was detected in six hospitalized children with acute leukemia. All the patients had respiratory symptoms and one of them suffered from parotitis.

Conclusion

Early diagnoses using multiplex real-time polymerase chain reaction (PCR) let us control this outbreak. A phylogenetic analysis confirmed person-to-person transmission of a single HPIV-3 variant.

[Persistent polyclonal B-cell lymphocytosis: study of 35 cases]

BACKGROUND AND OBJECTIVES

Persistent polyclonal B-cell lymphocytosis (PPBL) is a rare entity, presenting especially in adult smoker women. It is characterized by an increase of serum IgM, DR7-HLA haplotype, cytogenetic abnormalities and multiple IgH/BCL-2 rearrangements. To date, it has not been elucidated whether this is a benign or premalignant disorder. We analyzed the PPBL characteristics with especial attention to its evolution.

PATIENTS AND METHODS

Thirty-five PPBL patients from 5 hospitals in Catalonia were retrospectively analyzed. A simultaneous morphologic review of the blood smears was performed by members of the GCCH in a 16 multiple-observer optic microscope. Clinical and biological data were also analyzed.

RESULTS

PPBL presents in the majority of cases with persistent polyclonal B-cell lymphocytosis and affects primarily smoker women. The morphologic hallmark, in absence of viral infections, is the presence of activated lymphocytes with bilobulated and/or cleaved nuclei, and nuclear pockets in the ultrastructural study. Increased serum IgM, HLA-DR7 haplotype, chromosomal abnormalities such as i(3)(q10) and multiple IgH/BCL-2 rearrangements were detected. Thirty-four out of 35 patients are alive after a median follow up of 70.7 months. One patient died because of lung adenocarcinoma and another developed a follicular lymphoma without relation to PPBL.

CONCLUSIONS

PPBL has an asymptomatic and stable evolution, although it frequently presents genetic abnormalities. It remains unknown whether it is a premalignant entity, similar to monoclonal gammopathies of unknown significance. Hence, accurate cytologic diagnosis and follow-up are essential.

XPC genetic polymorphisms correlate with the response to imatinib treatment in patients with chronic phase chronic myeloid leukemia

Chronic myeloid leukemia (CML) is driven by the BCR-ABL protein, which promotes the proliferation and viability of the leukemic cells. Moreover, BCR-ABL induces genomic instability that can contribute to the emergence of resistant clones to the ABL kinase inhibitors. It is currently unknown whether the inherited individual capability to repair DNA damage could affect the treatment results. To address this, a comprehensive analysis of single nucleotide polymorphisms (SNPs) on the nucleotide excision repair (NER) genes (ERCC2-ERCC8, RPA1-RPA3, LIG1, RAD23B, XPA, XPC) was performed in 92 chronic phase CML patients treated with imatinib upfront. ERCC5 and XPC SNPs correlated with the response to imatinib. Haplotype analysis of XPC showed that the wild-type haplotype (499C-939A) was associated with a better response to imatinib. Moreover, the 5-year failure free survival for CA carriers was significantly better than that of the non-CA carriers (98% vs. 73%; P = 0.02). In the multivariate logistic model with genetic data and clinical covariates, the hemoglobin (Hb) level and the XPC haplotype were independently associated with the treatment response, with patients having a Hb < or =11 g/dl (Odds ratio [OR] = 5.0, 95% confidence interval [CI] = 1.5-16.1) or a non-CA XPC haplotype (OR = 4.1, 95% CI = 1.6-10.6) being at higher risk of suboptimal response/treatment failure. Our findings suggest that genetic polymorphisms in the NER pathway may influence the results to imatinib treatment in CML.

Genetic changes including gene copy number alterations and their relation to prognosis in childhood acute myeloid leukemia

We studied a series of 68 subjects diagnosed with childhood acute myeloid leukemia (AML) using conventional cytogenetics and fluorescence in situ hybridization (FISH), polymerase chain reaction (PCR) to analyze mutations in FLT3 and NPM1 genes, and/or array comparative genomic hybridization (CGH). Cytogenetic/FISH abnormalities were observed in 71% of subjects, FLT3-ITD mutations in 15%, and NPM1 mutations in 13%. The array CGH alterations (average 3.6 per case) were observed in 96% of the tested subjects. The most frequent alterations were gains of 8q24.3 and 11p15.5-p15.4 in 16% of the samples. Six genes (AKT1, RUNX1, LTB, SDC1, RUNX1T1, and JAK2) from the imbalanced regions have been reported to be involved in AML, whereas other 30 cancer genes, not previously reported in an AML context, were identified as imbalanced. They probably correspond to non passenger alterations that cooperate with the recurrent translocations. The clinical data and genetic changes were tested to find out the possible association with prognosis. Genomic instability (four or more genomic imbalances) was correlated with poor patient outcome (p = 0.029).

Pandemic influenza A (2009 H1N1) in children with acute lymphoblastic leukaemia

Pandemic influenza A (2009-H1N1) usually results in mild clinical illness, but in some individuals it can be life-threatening. There are no reports of this disease among paediatric patients with acute lymphoblastic leukaemia (ALL). We report ten consecutive patients with ALL and pandemic influenza treated in a single institution. Median age was 7 years (range: 3-12). All were treated with oseltamivir. There were no deaths. Two patients under intensive chemotherapy developed pneumonia and one required ventilatory support. ALL patients under maintenance treatment had mild disease. In conclusion, in our series only patients under intensive treatment developed a moderate to severe disease.

Primary Cutaneous Small/Medium CD4+ T-Cell Lymphomas: A Heterogeneous Group of Tumors With Different Clinicopathologic Features and Outcome

Purpose

To define the clinical and pathologic characteristics of primary cutaneous small/medium CD4+ T-cell lymphoma (PCSM-TCL) and identify parameters of prognostic significance.

Patients and Methods

We have investigated 24 patients with primary cutaneous lymphomas composed of small/medium mature T-cells with a βF1, CD3, CD4+ and/or noncytotoxic, CD8– and CD30– phenotype. The proliferation index and CD8+ infiltrating cells were quantified with an automated image analysis system.

Results

Sixteen patients presenting with solitary or localized plaques or small nodules (< 3 cm) had an indolent course. Only three patients experienced repeated cutaneous relapses, and none of them died as a result of the disease after 1 to 168 months (median, 17 months) of follow-up. The tumors had a low proliferation (median Ki-67, 9% ± 5%) and an intense infiltrate of reactive CD8+ (median, 20% ± 11.7%). Five patients presenting with rapidly evolving large tumors or nodules (≥ 5 cm) had an aggressive disease and died with extracutaneous dissemination 18 to 36 months after diagnosis (median, 23 months). These tumors had a significantly higher proliferation (median Ki-67, 22% ± 11.3%; P < .05) and lower number of infiltrating CD8+ (median, 1% ± 3%; P < .05) than the previous group. A third group of three patients had a peculiar clinical presentation with multifocal relapsing lesions without extracutaneous dissemination after a long period of follow-up ranging from 41 to 92 months. Histologically, these cases had an intense infiltrate of eosinophils.

Conclusion

PCSM-TCL is a heterogeneous group of tumors with differentiated clinical and pathological characteristics with impact in the outcome of the patients.

Gene expression profiling of acute myeloid leukemia with translocation t(8;16)(p11;p13) and MYST3-CREBBP rearrangement reveals a distinctive signature with a specific pattern of HOX gene expression

Acute myeloid leukemia (AML) with translocation t(8;16)(p11;p13) is an infrequent leukemia subtype with characteristic clinicobiological features. This translocation leads to fusion of MYST3 (MOZ) and CREBBP (CBP) genes, probably resulting in a disturbed transcriptional program of a myelomonocytic precursor. Nonetheless, its gene expression profile is unknown. We have analyzed the gene expression profile of 23 AML patients, including three with molecularly confirmed MYST3-CREBBP fusion gene, using oligonucleotide U133A arrays (Affymetrix). MYST3-CREBBP cases clustered together and clearly differentiated from samples with PML-RARalpha, RUNX1-RUNX1T1, and CBFbeta-MYH11 rearrangements. The relative expression of 46 genes, selected according to their differential expression in the high-density array study, was analyzed by low-density arrays in an additional series of 40 patients, which included 7 MYST3-CREBBP AML cases. Thus, genes such as prolactin (PRL) and proto-oncogene RET were confirmed to be specifically overexpressed in MYST3-CREBBP samples whereas genes such as CCND2, STAT5A, and STAT5B were differentially underexpressed in this AML category. Interestingly, MYST3-CREBBP AML exhibited a characteristic pattern of HOX expression, with up-regulation of HOXA9, HOXA10, and cofactor MEIS1 and marked down-regulation of other homeobox genes. This profile, with overexpression of FLT3, HOXA9, MEIS1, AKR7A2, CHD3, and APBA2, partially resembles that of AML with MLL rearrangement. In summary, this study shows the distinctive gene expression profile of MYST3-CREBBP AML, with overexpression of RET and PRL and a specific pattern of HOX gene expression.

Molecular biology in acute leukemia

Acute leukemia is a clonal expansion of tumoral cells in bone marrow, blood or other tissues. The acute leukemias are classified as myeloid or lymphoid based on the lineage of the blast cells. Over the past three decades, remarkable advances have been made in the classification and treatment of acute leukemias. In the last years, the research into the molecular pathogenesis of acute leukemia has progressed. The knowledge of chromosomal translocations breakpoints and possible candidate oncogenes and tumor suppressor genes has allowed the integration of all these events into multistep cascades that impact specific signal transduction pathways and lead to leukemic transformation.

ZAP-70 expression in normal pro/pre B cells, mature B cells, and in B-cell acute lymphoblastic leukemia

PURPOSE

The ZAP-70 gene is normally expressed in T and natural killer cells, where it is required for the T-cell receptor (TCR) signaling. More recently, it has been described that ZAP-70 contributes to the B-cell development at early stages of B-cell differentiation in mice. The purpose was to investigate the presence of ZAP-70 in normal pro/pre B cells and mature B cells and in tumoral cells from B-acute lymphoblastic leukemias (B-ALL).

EXPERIMENTAL DESIGN

ZAP-70 expression was ascertained by flow cytometry, immunofluorescence, Western blot, and quantitative reverse transcription-PCR. Analysis of ZAP-70 and other signaling proteins of the pre-TCR/TCR was done by Western blot.

RESULTS

ZAP-70 was expressed in pro/pre B cells but not in normal mature B cells derived from bone marrow, peripheral blood, or tonsil. Among tumoral cells, ZAP-70 was expressed in 56% of B-ALLs with pro/pre B-cell phenotype and in 4 of 6 Burkitt/ALL lymphomas. In B-ALL cells, expression of CD38 protein correlated with ZAP-70 expression (P = 0.05). Mutational analysis of the ZAP-70 gene revealed the absence of mutations in cases lacking ZAP-70 expression. Moreover, other elements of the pre-TCR/TCR signaling pathway, like LAT and Lck, were also found in B-ALL cells.

CONCLUSIONS

Among normal B-cell subsets, ZAP-70 was found expressed in normal pro/pre B cells but not in a significant proportion of normal B cells with mature phenotype. Moreover, the presence of ZAP-70 in B-ALLs probably reflects their cellular origin. The lack of ZAP-70 expression in normal mature B cells suggests that its expression in mature-derived neoplasms with different cellular origin, such as Burkitt's lymphoma and chronic lymphocytic leukemia, might be due to an aberrant phenomenon.

Studies of complex Ph translocations in cases with chronic myelogenous leukemia and one with acute lymphoblastic leukemia

The BCR/ABL gene fusion, the hallmark of chronic myelogenous leukemia (CML) is generated in 2-10% of patients by a variant Ph translocation involving 9q34, 22q11.2, and one or more additional genomic regions. The objective of this study was the characterization by conventional and molecular cytogenetics of complex variant Ph translocations present at diagnosis. FISH studies were performed in 7 cases using the LSI BCR/ABL ES probe allowing the detection of the fusion BCR/ABL gene on the Ph chromosome in all of them and 9q34 deletions in 2 cases. Three cryptic complex rearrangements were detected by FISH studies. The third and the fourth chromosome regions involved in the 8 complex variant translocations were: 1q21, 1p36, 5q31, 11q13, 12q13, 12p13, and 20q12. In conclusion, FISH studies have been useful in the detection of the BCR/ABL rearrangements and 9q34 deletions, and to identify complex rearrangements that differ from the ones previously established by conventional cytogenetics.

Predictive value of Follicular Lymphoma International Prognostic Index (FLIPI) in patients with follicular lymphoma at first progression

BACKGROUND

Different prognostic scores have been proposed to predict the outcome of follicular lymphoma (FL) patients at diagnosis. A new prognostic index specifically addressing FL patients, the Follicular Lymphoma International Prognostic Index (FLIPI), has recently been developed, which might also be useful in patients with progression.

PATIENTS AND METHODS

One hundred and three patients (55 male, 48 female; median age 59 years) with FL in first relapse/progression after an initial response to therapy (50 complete responders/ 53 partial responders) were included in the study.

RESULTS

Five-year survival from progression (SFP) was 55% (95% confidence interval 44%-66%). The distribution according to the FLIPI at relapse was 39% good prognosis, 24% intermediate prognosis and 37% poor prognosis. Five-year SFP for these groups were 85%, 79% and 28%, respectively (P < 0.0001). Other variables at relapse with prognostic significance for SFP were age, presence of B symptoms, performance status, bulky disease, number of involved nodal sites, lactate dehydrogenase level, hemoglobin level, histological transformation, the Italian Lymphoma Intergroup prognostic index for FL and the International Prognostic Index for aggressive lymphomas. In the multivariate analysis bulky disease (P=0.01), presence of B symptoms (P=0.03) and FLIPI at relapse (P=0.0003) were the most important variables for predicting SFP.

CONCLUSIONS

In patients with FL at first relapse/progression, the FLIPI, along with the presence of bulky disease and B symptoms, are features that predict SFP and thus could be useful to select candidates for experimental treatments.

Type I MOZ/CBP (MYST3/CREBBP) is the most common chimeric transcript in acute myeloid leukemia with t(8;16)(p11;p13) translocation

The t(8;16)(p11;p13) fuses the MOZ (MYST3) gene at 8p11 with CBP (CREBBP) at 16p13 and is associated with an infrequent but well-defined type of acute myeloid leukemia (AML) that has unique morphocytochemical findings (monocytoid blast morphology with erythrophagocytosis and simultaneously positive for myeloperoxidase and nonspecific esterases). RT-PCR amplification of MOZ/CBP (MYST3/CREBBP) chimera has proved difficult, with four different transcripts found in four reported cases. We studied 7 AML-t(8;16) patients, 5 with cytogenetically demonstrated t(8;16) and 2 with similar morphocytochemical and immunophenotypical characteristics. Clinically, 3 cases presented as therapy-related leukemia. Extramedullar involvement was observed at presentation in 2 patients and coagulopathy in 4. The clinicobiological findings confirmed the distinctiveness of this entity. Of note is the erythrophagocytosis in 5 of 7 cases and the immunological negativity for CD34 and CD117 and positivity for CD56. Using a new RT-PCR strategy, we were able to amplify a specific band of 212 bp in six cases in which sequence analysis confirmed the presence of the previously described MOZ/CBP fusion transcript type I. This is the largest molecularly studied AML-t(8;16) series, which demonstrates that MOZ/CBP breakpoints are usually clustered in intron 16 of MOZ and intron 2 of CBP. The newly designed single-round PCR provides a simple tool for the molecular confirmation of MOZ/CBP rearrangement.

Polyethylene glycol interferon-alpha2b alone or in combination with low-dose Ara-C in patients newly diagnosed with chronic myeloid leukemia

Thirty-five patients newly diagnosed with chronic myeloid leukemia received pegylated interferon alpha-2b (PEG-IFN) alone or combined with intermittent Ara-C for a median of 6.5 months (range: 1.4-19.2). The median weekly PEG-IFN dose was 4.0 microg/kg. Complete hematologic, major and complete cytogenetic responses were observed in 73%, 32% and 14%, respectively. Extra-hematologic side-effects were frequent and 20% of patients had grade III-IV hematologic toxicity.

Increased incidence of acute myeloid leukemia after liver transplantation? Description of three new cases and review of the literature

BACKGROUND

Acute myeloid leukemia (AML) after solid organ transplantation is rare, with only six AML cases after liver transplantation (LT) being reported.

METHODS

Characteristics of three AML cases observed among 799 recipients of LT in the authors' institution and estimation of the standardized incidence ratio (SIR) are presented.

RESULTS

Three AML cases were diagnosed (French-American-British classification subtypes M0, M3, and M1) at 38 days, 2 years, and 3.5 years after LT, respectively. The immunosuppressive regimen consisted of cyclosporine A and prednisone. The recipient's origin of blasts could be demonstrated in two cases. All patients achieved complete remission after standard treatment. Nonetheless, disease relapsed in two patients at 2 and 6 months, whereas the patient with acute promyelocytic leukemia remains disease-free 4 years after diagnosis. As compared with the general population, the observed incidence of AML in the authors' series of LT results in a significantly higher SIR of 11.41 (P=0.0023).

CONCLUSIONS

The higher SIR found in the authors' series suggests an increased risk of AML in patients undergoing LT.

Imatinib mesylate therapy of chronic phase chronic myeloid leukemia resistant or intolerant to interferon: results and prognostic factors for response and progression-free survival in 150 patients

BACKGROUND AND OBJECTIVES

Imatinib mesylate has recently been shown to be highly effective in chronic-phase chronic myeloid leukemia (CML). The results of imatinib treatment in chronic-phase CML patients resistant or intolerant to interferon (IFN) and the factors predicting therapeutic response and progression-free survival were analyzed.

DESIGN AND METHODS

One hundred and fifty patients with chronic-phase CML resistant (n=111) or intolerant (n=39) to IFN were treated with imatinib. Prognostic factors for response and disease progression were assessed by multivariate analysis.

RESULTS

The median time from diagnosis was 43 months (0.5-188), median IFN therapy 21.5 months (0.5-140) and median follow-up from starting imatinib 13.6 months (range: 3-23). Complete hematologic response was achieved in 96 of 97 patients. Complete, partial and minor cytogenetic responses were present in 44%, 22%, and 8% of patients at 12 months. Grade III-IV neutropenia, thrombocytopenia, and anemia developed in 33%, 16%, and 6% of patients, respectively. Sixty-five patients discontinued treatment for a median of 4 weeks (1-36) due to toxicity. The rate of progression-free survival (lack of accelerated/blastic phase with persistent response) was 89.2% (95% CI: 84-94.4) at 12 months and 80.2% (95% CI: 72.2-88.2) at 18 months. Platelets > 450x10(9)/L and treatment discontinuation > 4 weeks were associated with a lower rate of major (complete plus partial) cytogenetic response. Patients in Sokal's high-risk group and those who did not achieve a major cytogenetic response had significantly shorter progression-free survival.

INTERPRETATION AND CONCLUSIONS

Imatinib is highly effective in chronic-phase CML patients resistant or intolerant to IFN, especially in those with normal platelet counts and in those not requiring prolonged treatment discontinuation due to neutropenia.

Idiopathic myelofibrosis associated with classic polyarteritis nodosa

A woman with scleroderma and classic polyarteritis nodosa (PAN) who developed idiopathic myelofibrosis (IM) is reported. The patient presented with a one-year history of weakness, polyarthritis, Raynaud phenomenon, dry cough, and epigastralgia. The diagnosis of scleroderma with visceral involvement was made and treatment with prednisone subsequently started, with good clinical response. Six years later, fever, weight loss, livedo reticularis, and dysesthesias developed. Electromyographic studies were consistent with sensory neuropathy and a sural nerve biopsy yielded the diagnosis of PAN. The patient received cyclophosphamide plus prednisone with a favorable response, but 11 years later she was admitted because of weakness, constitutional symptoms, and abdominal pain due to spleen infarcts. Marked anemia, with aniso-poikilocytosis, tear-drop cells, immature myeloid precursors in the peripheral blood, and an increased serum LDH, was observed and the diagnosis of IM established by bone marrow biopsy. This case represents a new association between IM and an autoimmune disease and supports the hypothesis of an immune basis of IM in some patients.

Imatinib mesylate (STI571) treatment in patients with chronic-phase chronic myelogenous leukaemia previously submitted to autologous stem cell transplantation

Imatinib mesylate (STI571) is a highly effective and well-tolerated treatment for patients with chronic-phase chronic myeloid leukaemia (CML), but information on its efficacy and tolerance in intensively pretreated patients is scarce. Thirty-three chronic-phase CML patients who were resistant or intolerant to interferon (IFN) and had been previously submitted to autologous stem cell transplantation were treated with imatinib for a median of 14 months (range: 6-19 months). Seven patients were in haematological response (HR) at the start of treatment; the remaining 26 attained a HR at a median of 3 weeks (range: 1-4 weeks). Major cytogenetic response rates at 3, 6 and 12 months were 42%, 45% and 55%, respectively, including 21%, 24% and 33% complete responses. Grade 3-4 neutropenia, thrombocytopenia and anaemia developed in 33%, 27% and 12% of patients respectively. Non-haematological toxicity included superficial oedema (21% of patients), gastrointestinal symptoms (18%), muscle cramps (15%), skin rash and liver enzyme increase (3% each). These results were not significantly different from those in 65 chronic-phase CML patients, resistant or intolerant to interferon without a previous ASCT, who were included in the same protocol. Imatinib mesylate is effective and safe in chronic-phase CML patients with a previous history of intensive treatment.

Survival after progression in patients with follicular lymphoma: analysis of prognostic factors

BACKGROUND

The purpose of this study was to identify prognostic parameters for patients with follicular lymphoma (FL) in first progression/relapse. These would be useful for selection of high-risk patients for inclusion in trials aimed at determining the effect of new treatment approaches in such patients.

PATIENTS AND METHODS

Ninety patients (48 male, 42 female, median age 56 years) diagnosed with FL, in a single institution during a 20 year period and relapsing/progressing after an initial response to therapy, were recruited. The main end-point of the study was survival from progression (SFP). Univariate and multivariate analyses were performed, including among the predictive variables the response duration (RD) after the initial treatment and the main features of the patients at the first progression or relapse.

RESULTS

Five-year SFP was 47% (95% confidence interval 35% to 58%). Patients with RD following initial therapy >2 years had a longer SFP (5-year SFP 63 versus 33%, P = 0.012). Other variables with prognostic interest for SFP were stage at diagnosis and the following variables at relapse: age, bulky disease, performance status, serum lactate dehydrogenase level, serum beta2-microglobulin level, bone marrow involvement, stage and International Prognostic Index rating. In the multivariate analysis, poor performance status at progression and a RD <2 years were the most important unfavorable variables to predict SFP.

CONCLUSION

In patients with FL, RD along with performance status at progression are features that predict SFP. These variables could thus be useful to select candidates for experimental treatments.