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Biomedical subjects

Donna Neuberg

Publications and source records attributed to Donna Neuberg.

At least 37 records · Page 2Linked to original sources

Increasing incidence of late second malignancies after conditioning with cyclophosphamide and total-body irradiation and autologous bone marrow transplantation for non-Hodgkin's lymphoma.

PURPOSE: Although the risk of myelodysplastic syndrome (MDS) has been well-described following autologous bone marrow transplantation (ABMT), the risk of solid tumors has been poorly characterized. We report the incidence and outcome of solid tumors at 10-year follow-up in a large cohort of uniformly treated patients who underwent ABMT for non-Hodgkin's lymphoma (NHL). PATIENTS AND METHODS: Between 1982 and 1997, 605 patients underwent ABMT for B-cell NHL, with uniform conditioning with cyclophosphamide and total-body irradiation followed by reinfusion of autologous bone marrow purged with anti-B-cell monoclonal antibodies. Current information on relapse of disease and second malignancies was obtained via an institutional review board-approved questionnaire sent to the referring oncologists. RESULTS: Forty-two solid tumors, six non-MDS hematologic malignancies, 39 nonmelanoma skin cancers, and 68 cases of MDS/acute myelogenous leukemia (AML) were observed at a median follow-up of 9.5 years. A cumulative incidence model using death as a competing risk found that the 10-year incidence of second malignancy is 21%, with 10.0% non-MDS malignancies. The projected incidence of all malignancies at 15 years is 29%. The principal risk factor for second malignancy is increased age at ABMT (P = .0002). In the entire cohort, 9.6% of patients have died of second malignancy. CONCLUSION: Lengthy follow-up demonstrates a significant incidence of second malignancies after ABMT for NHL. Although the incidence of MDS/AML starts to plateau, the incidence of solid tumors continues to rise. Second malignancies are responsible for a significant fraction of overall mortality following ABMT.

Adult↗

Polymorphisms in ERCC1 and grade 3 or 4 toxicity in non-small cell lung cancer patients.

PURPOSE: ERCC1 is a lead enzyme in the nucleotide excision repair pathway of DNA repair. Polymorphisms have been identified in the ERCC1 gene, the C8092A and codon 118 polymorphisms, which may lead to an altered capacity to regenerate damaged normal tissue and greater treatment-related toxicity. EXPERIMENTAL DESIGN: Using logistic regression models, we evaluated the ERCC1 C8092A and codon 118 polymorphisms and their association with the occurrence of grade 3 or 4 toxicity in 214 stage III and IV non-small cell lung cancer patients treated first line with platinum-based chemotherapy. Adjusting covariates were performance status and type of treatment regimen. RESULTS: There was no statistically significant association between either the C8092A or codon 118 polymorphism and overall or hematologic grade 3 or 4 toxicity. However, carrying at least one variant ERCC1 C8092A allele was associated with a significantly increased risk of grade 3 or 4 gastrointestinal toxicity (adjusted odds ratio, 2.33; 95% confidence interval, 1.07-5.05; P = 0.03). CONCLUSIONS: Adjusting for performance status and type of treatment regimen, carrying at least one ERCC1 8092A allele is associated with a >2-fold increase in grade 3 or 4 gastrointestinal toxicity among platinum-treated non-small cell lung cancer patients.

Adult↗

Genetic linkage of prostate cancer risk to the chromosome 3 region bearing FHIT.

We conducted linkage analysis of 80 candidate genes in 201 brother pairs affected with prostatic adenocarcinoma. Markers representing two adjacent candidate genes on chromosome 3p, CDC25A and FHIT, showed suggestive evidence for linkage with single-point identity-by-descent allele-sharing statistics. Fine-structure multipoint linkage analysis yielded a maximum LOD score of 3.17 (P = 0.00007) at D3S1234 within FHIT intron 5. For a subgroup of 38 families in which three or more affected brothers were reported, the LOD score was 3.83 (P = 0.00001). Further analysis reported herein suggested a recessive mode of inheritance. Association testing of 16 single nucleotide polymorphisms (SNP) spanning a 381-kb interval surrounding D3S1234 in 202 cases of European descent with 143 matched, unrelated controls revealed significant evidence for association between case status and the A allele of single nucleotide polymorphism rs760317, located within intron 5 of FHIT (Pearson's chi(2) = 8.54, df = 1, P = 0.0035). Our results strongly suggest involvement of germline variations of FHIT in prostate cancer risk.

Acid Anhydride Hydrolases↗

tp53 mutant zebrafish develop malignant peripheral nerve sheath tumors.

TP53 is the most frequently mutated tumor suppressor gene in human cancer, with nearly 50% of all tumors exhibiting a loss-of-function mutation. To further elucidate the genetic pathways involving TP53 and cancer, we have exploited the zebrafish, a powerful vertebrate model system that is amenable to whole-genome forward-genetic analysis and synthetic-lethal screens. Zebrafish lines harboring missense mutations in the tp53 DNA-binding domain were identified by using a target-selected mutagenesis strategy. Homozygous mutant fish from two of these lines were viable and exhibited mutations similar to those found in human cancers (tp53(N168K) and tp53(M214K)). Although homozygous tp53(N168K) mutants were temperature-sensitive and suppressed radiation-induced apoptosis only at 37 degrees C, cells in the tp53(M214K) embryos failed to undergo apoptosis in response to gamma radiation at both 28 and 37 degrees C. Unlike wild-type control embryos, irradiated tp53(M214K) embryos also failed to up-regulate p21 and did not arrest at the G(1)/S checkpoint. Beginning at 8.5 months of age, 28% of tp53(M214K) mutant fish developed malignant peripheral nerve sheath tumors. In addition to providing a model for studying the molecular pathogenic pathways of malignant peripheral nerve sheath tumors, these mutant zebrafish lines provide a unique platform for modifier screens to identify genetic mutations or small molecules that affect tp53-related pathways, including apoptosis, cell-cycle delay, and tumor suppression.

Alleles↗

Characterization of AMN107, a selective inhibitor of native and mutant Bcr-Abl.

The Bcr-Abl tyrosine kinase oncogene causes chronic myelogenous leukemia (CML) and Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL). We describe a novel selective inhibitor of Bcr-Abl, AMN107 (IC50 <30 nM), which is significantly more potent than imatinib, and active against a number of imatinib-resistant Bcr-Abl mutants. Crystallographic analysis of Abl-AMN107 complexes provides a structural explanation for the differential activity of AMN107 and imatinib against imatinib-resistant Bcr-Abl. Consistent with its in vitro and pharmacokinetic profile, AMN107 prolonged survival of mice injected with Bcr-Abl-transformed hematopoietic cell lines or primary marrow cells, and prolonged survival in imatinib-resistant CML mouse models. AMN107 is a promising new inhibitor for the therapy of CML and Ph+ ALL.

Animals↗

Failure to define window of time for autologous tumor vaccination in patients with newly diagnosed or relapsed acute lymphoblastic leukemia.

OBJECTIVES: We and others have shown that B cell precursor acute lymphoblastic leukemia cells (ALL) stimulated with CD40 ligand become efficient antigen-presenting cells (APC) capable of expanding autologous, tumor-specific T cells from patients. Translation of these preclinical findings to a novel treatment strategy required four separate issues to be determined: (1) if a CD40-ALL vaccine could be generated for clinical use; (2) whether clinical translation could be achieved; (3) whether the vaccination was safe; and (4) whether a window of time could be identified that would optimize the efficacy of vaccination. PATIENTS AND METHODS: Nine patients with relapsed/refractory ALL were enrolled in a phase I trial of vaccination with autologous CD40-ALL. Immunologic reconstitution was measured in a separate cohort of 23 patients with newly diagnosed ALL. RESULTS: We successfully prepared autologous vaccines for all nine patients in the phase I trial. CD40-ALL were potent APC, capable of stimulating allogeneic and peptide-specific T cells in vitro. Two patients were vaccinated without adverse events. Five patients died or progressed before vaccination, suggesting that rapid disease progression limits vaccination in patients with relapse disease, thus limiting clinical translation. We therefore sought to identify a window of time for vaccination during which this approach might be feasible. To achieve this end, we evaluated immunological reconstitution in newly diagnosed patients with ALL patients. Despite recovery of myelopoiesis, most patients had profound defects in T, B, and natural killer (NK) cell numbers that failed to recover at any point during therapy. CONCLUSION: Autologous tumor vaccination at a time of ALL relapse is not feasible. Alternative strategies for immunotherapy of ALL may require ex vivo generation of antigen specific T cells and adoptive therapy.

Adolescent↗

A feasibility trial of antiangiogenic (metronomic) chemotherapy in pediatric patients with recurrent or progressive cancer.

Standard chemotherapeutic drugs, when modified by the frequency and dose of administration, can target angiogenesis. This approach is referred to as antiangiogenic chemotherapy, low-dose chemotherapy, or metronomic chemotherapy. This study evaluated the feasibility of 6 months of metronomic chemotherapy, its toxicity and tolerability, surrogate markers of activity, and preliminary evidence of activity in children with recurrent or progressive cancer. Twenty consecutive children were enrolled and received continuous oral thalidomide and celecoxib with alternating oral etoposide and cyclophosphamide every 21 days for a planned duration of 6 months using antiangiogenic doses of all four drugs. Surrogate markers including bFGF, VEGF, endostatin, and thrombospondin were also evaluated. Therapy was well tolerated in this heavily pretreated population. Toxicities (predominantly reversible bone marrow suppression) responded to dose modifications. Sixty percent of the patients received less than the prescribed 6 months of therapy due to toxicity (one case of deep vein thrombosis), personal choice (1 patient), or disease progression (10 patients). Forty percent of the patients completed the 6 months of therapy, resulting in prolonged or persistent disease-free status. One quarter of all patients continue to be progression free more than 123 weeks from starting therapy. Sixteen percent of patients showed a radiographic partial response. Only elevated thrombospondin-1 levels appeared to correlate with prolonged response. This oral antiangiogenic chemotherapy regimen was well tolerated in this heavily pretreated pediatric population, which showed prolonged or persistent disease-free status, supporting the continued study of antiangiogenic/metronomic chemotherapy in human clinical trials.

Administration, Oral↗

Molecular profiling of diffuse large B-cell lymphoma identifies robust subtypes including one characterized by host inflammatory response.

Diffuse large B-cell lymphoma (DLBCL) is a heterogeneous disease with recognized variability in clinical outcome, genetic features, and cells of origin. To date, transcriptional profiling has been used to highlight similarities between DLBCL tumor cells and normal B-cell subtypes and associate genes and pathways with unfavorable outcome. To identify robust and highly reproducible DL-BCL subtypes with comprehensive transcriptional signatures, we used a large series of newly diagnosed DLBCLs, whole genome arrays, and multiple clustering methods. Tumors were also analyzed for known common genetic abnormalities in DLBCL. There were 3 discrete subsets of DLBCL-"oxidative phosphorylation," "B-cell receptor/proliferation," and "host response" (HR)-identified characterized using gene set enrichment analysis and confirmed in an independent series. HR tumors had increased expression of T/natural killer cell receptor and activation pathway components, complement cascade members, macrophage/dendritic cell markers, and inflammatory mediators. HR DLB-CLs also contained significantly higher numbers of morphologically distinct CD2+/CD3+ tumor-infiltrating lymphocytes and interdigitating S100+/gamma interferon-induced lysosomal transferase-positive (GILT+) CD1a-/CD123- dendritic cells. The HR cluster shared features of histologically defined T-cell/histiocyte-rich B-cell lymphoma, including fewer genetic abnormalities, younger age at presentation, and frequent splenic and bone marrow involvement. These studies identify tumor microenvironment and host inflammatory response as defining features in DLBCL and suggest rational treatment targets in specific DLBCL subsets.

Cluster Analysis↗

Comparison of frozen and RNALater solid tissue storage methods for use in RNA expression microarrays.

BACKGROUND: Primary human tissues are an invaluable widely used tool for discovery of gene expression patterns which characterize disease states. Tissue processing methods remain unstandardized, leading to unanswered concerns of how to best store collected tissues and maintain reproducibility between laboratories. We subdivided uterine myometrial tissue specimens and stored split aliquots using the most common tissue processing methods (fresh, frozen, RNALater) before comparing quantitative RNA expression profiles on the Affymetrix U133 human expression array. Split samples and inclusion of duplicates within each processing group allowed us to undertake a formal genome-wide analysis comparing the magnitude of result variation contributed by sample source (different patients), processing protocol (fresh vs. frozen vs. 24 or 72 hours RNALater), and random background (duplicates). The dataset was randomly permuted to define a baseline pattern of ANOVA test statistic values against which the observed results could be interpreted. RESULTS: 14,639 of 22,283 genes were expressed in at least one sample. Patient subjects provided the greatest sources of variation in the mixed model ANOVA, with replicates and processing method the least. The magnitude of variation conferred by processing method (24 hours RNALater vs 72 hours RNALater vs. fresh vs frozen) was similar to the variability seen within replicates. Subset analysis of the test statistic according to gene functional class showed that the frequency of "outlier" ANOVA results within each functional class is overall no greater than expected by chance. CONCLUSIONS: Ambient storage of tissues for 24 or 72 hours in RNALater did not contribute any systematic shift in quantitative RNA expression results relative to the alternatives of fresh or frozen tissue. This nontoxic preservative enables decentralized tissue collection for expression array analysis without a requirement for specialized equipment.

Analysis of Variance↗

Patients with acute myeloid leukemia and an activating mutation in FLT3 respond to a small-molecule FLT3 tyrosine kinase inhibitor, PKC412.

Leukemic cells from 30% of patients with acute myeloid leukemia (AML) have an activating mutation in the FLT3 (fms-like tyrosine kinase) gene, which represents a target for drug therapy. We treated 20 patients, each with mutant FLT3 relapsed/refractory AML or high-grade myelodysplastic syndrome and not believed to be candidates for chemotherapy, with an FLT3 tyrosine kinase inhibitor, PKC412 (N-benzoylstaurosporine), at a dose of 75 mg 3 times daily by mouth. The drug was generally well tolerated, although 2 patients developed fatal pulmonary events of unclear etiology. The peripheral blast count decreased by 50% in 14 patients (70%). Seven patients (35%) experienced a greater than 2-log reduction in peripheral blast count for at least 4 weeks (median response duration, 13 weeks; range, 9-47 weeks); PKC412 reduced bone marrow blast counts by 50% in 6 patients (2 of these to < 5%). FLT3 autophosphorylation was inhibited in most of the Corresponding patients, indicating in vivo target inhibition at the dose schedule used in this study. PKC412 is an oral tyrosine kinase inhibitor with clinical activity in patients with AML whose blasts have an activating mutation of FLT3, suggesting potential use in combination with active agents, such as chemotherapy.

Adult↗

Differential regulation of gene expression following CD40 activation of leukemic compared to healthy B cells.

It is possible to differentiate malignant from healthy cells and to classify diseases based on identification of specific gene expression profiles. We hypothesized that gene expression profiling could also be used to identify differential activation of healthy and malignant cells, and as a model for this, we examined the molecular sequelae of CD40 activation of healthy and B-cell chronic lymphocytic leukemia (CLL) cells. Hierarchical clustering analysis of gene expression signatures grouped samples by CD40 activation status and further subclassified CD40-activated CLL cells from healthy B cells. Supervised analyses in healthy B cells compared to CLL cells identified differential regulation of genes governing cell cycle progression and apoptosis. CD40 signaling of CLL cells increases their susceptibility to immune recognition, but promotes survival and cell cycle arrest, making these cells potentially more resistant to chemotherapy. These results illustrate the utility of gene expression profiling to elucidate the molecular sequelae of signaling in healthy cells and altered signaling pathways in malignant cells. This type of approach should be useful to identify targets of therapy of malignant diseases.

Adult↗

Mature results of a phase III randomized trial of bacillus Calmette-Guerin (BCG) versus observation and BCG plus dacarbazine versus BCG in the adjuvant therapy of American Joint Committee on Cancer Stage I-III melanoma (E1673): a trial of the Eastern Oncology Group.

BACKGROUND: The local and systemic effects of bacillus Calmette-Guerin (BCG) have been known for decades. To investigate the adjuvant effect of BCG on resected American Joint Committee on Cancer (AJCC) Stage I-III melanoma, the Eastern Cooperative Oncology Group conducted a large trial to study the use of BCG alone or a combination of BCG and dacarbazine between 1974 and 1978. METHODS: A total of 734 patients were randomized to 4 clinical groups consolidated into 2 cohorts. Cohort I compared BCG with observation and Cohort II compared BCG with a combination of BCG and dacarbazine. The primary end points were survival time and time to disease progression. RESULTS: Within Cohort I, no statistically significant difference in disease-free survival (DFS) (P = 0.84) or overall survival (OS) (5-year survival 67% vs. 62%; P = 0.40) was observed between BCG treatment and observation. Within Cohort II, the addition of dacarbazine to BCG did not improve DFS (P = 0.74) or OS (P = 0.81) compared with BCG alone. Toxicity was mild to moderate in both cohorts. Although toxicity with this agent is mild, the use of BCG is associated with the development of punctate abscesses in greater than two-thirds of patients treated. CONCLUSIONS: In what to our knowledge is the largest ever trial to test the role of BCG as adjuvant therapy for melanoma, no benefit for BCG was observed for patients with AJCC Stage I-III disease. The mature results of the current trial projected to 30 years confirmed the negative results of previous smaller studies utilizing this agent.

Adjuvants, Immunologic↗

Activating FLT3 mutations in CD117/KIT(+) T-cell acute lymphoblastic leukemias.

Activating FLT3 mutations are the most common genetic aberrations in acute myeloid leukemia (AML), resulting in the constitutive activation of this receptor tyrosine kinase (RTK), but such mutations are rarely found in acute lymphoblastic leukemia (ALL). Here we describe a unique subset of de novo adult T-cell ALL (T-ALL) cases that coexpress CD117/KIT and cytoplasmic CD3 (CD117/KIT(+) ALL). Activating mutations in the FLT3 RTK gene were found in each of 3 CD117/KIT(+) cases that were analyzed, but not in 52 other adult T-ALL samples from the same series that lacked CD117/KIT expression. Our results indicate the need for clinical trials to test the efficacy of drugs that inhibit the FLT3 RTK in this subset of patients with T-ALL.

Amino Acid Sequence↗

Outcome for children with group III rhabdomyosarcoma treated with or without radiotherapy.

PURPOSE: To analyze the sites of relapse, relapse-free survival, and overall survival in children with Group III rhabdomyosarcoma treated with or without radiotherapy (RT). METHODS AND MATERIALS: The outcomes of 48 children with Group III rhabdomyosarcoma treated between 1980 and 1997 were evaluated. The median overall survival follow-up was 7.3 years. Of the 48 patients, 65% had embryonal histology. Local treatment after induction chemotherapy included complete surgical resection (CSR) alone in 9 (19%), CSR plus RT in 13 (27%), partial resection or rebiopsy plus RT in 10 (21%), and RT alone in 15 patients (31%). One child developed distant disease before completing local therapy. RESULTS: Of the 48 patients, 12 developed relapse at local (n = 3), regional (n = 4), or distant (n = 5) sites. All 9 patients treated with CSR after induction chemotherapy had embryonal/botryoid histology. Only 1 of these 9 patients developed relapse. No statistically significant difference was found in overall survival (p = 0.95) or relapse-free survival (p = 0.67) between patients treated with or without RT. The Kaplan-Meier estimate of 5-year overall survival and relapse-free survival was 76% +/- 7% and 74% +/- 7%, respectively. Significant predictors of relapse-free survival on univariate analysis included CSR (p = 0.03), nodal positivity (p = 0.001), and embryonal histology (p = 0.0003). On multivariate analysis, embryonal histology was the most significant predictor of relapse-free (p = 0.001) and overall (p = 0.01) survival. CONCLUSION: The overall survival for children with Group III rhabdomyosarcoma in this series was favorable. Embryonal/botryoid histology was the most significant predictor of both overall and relapse-free survival. We found that for a selected subgroup of children with embryonal histology, induction chemotherapy followed by complete surgical resection alone may be adequate local therapy.

Adolescent↗

Utilization of Ig heavy chain variable, diversity, and joining gene segments in children with B-lineage acute lymphoblastic leukemia: implications for the mechanisms of VDJ recombination and for pathogenesis.

Sequence analysis of the immunoglobulin heavy chain genes (IgH) has demonstrated preferential usage of specific variable (V), diversity (D), and joining (J) genes at different stages of B-cell development and in B-cell malignancies, and this has provided insight into B-cell maturation and selection. Knowledge of the association between rearrangement patterns based on updated databases and clinical characteristics of pediatric acute lymphoblastic leukemia (ALL) is limited. We analyzed 381 IgH sequences identified at presentation in 317 children with B-lineage ALL and assessed the V(H)D(H)J(H) gene utilization profiles. The D(H)J(H)-proximal V(H) segments and the D(H)2 gene family were significantly overrepresented. Only 21% of V(H)-J(H) joinings were potentially productive, a finding associated with a trend toward an increased risk of relapse. These results suggest that physical location at the V(H) locus is involved in preferential usage of D(H)J(H)-proximal V(H) segments whereas D(H) and J(H) segment usage is governed by position-independent molecular mechanisms. Molecular pathophysiology appears relevant to clinical outcome in patients who have only productive rearrangements, and specific rearrangement patterns are associated with differences in the tumor biology of childhood ALL.

Adolescent↗

Combination of rapamycin and protein tyrosine kinase (PTK) inhibitors for the treatment of leukemias caused by oncogenic PTKs.

Abnormal protein tyrosine kinases (PTKs) cause many human leukemias. For example, BCR/ABL causes chronic myelogenous leukemia (CML), whereas FLT3 mutations contribute to the pathogenesis of acute myelogenous leukemia. The ABL inhibitor Imatinib (Gleevec, STI571) has remarkable efficacy for treating chronic phase CML, and FLT3 inhibitors (e.g., PKC412) show similar promise in preclinical studies. However, resistance to PTK inhibitors is a major emerging problem that may limit long-term therapeutic efficacy. Development of rational combination therapies will probably be required to effect cures of these and other neoplastic disorders. Here, we report that the mTOR inhibitor rapamycin synergizes with Imatinib against BCR/ABL-transformed myeloid and lymphoid cells and increases survival in a murine CML model. Rapamycin/Imatinib combinations also inhibit Imatinib-resistant mutants of BCR/ABL, and rapamycin plus PKC412 synergistically inhibits cells expressing PKC412-sensitive or -resistant leukemogenic FLT3 mutants. Biochemical analyses raise the possibility that inhibition of 4E-BP1 phosphorylation may be particularly important for the synergistic effects of PTK inhibitor/rapamycin combinations. Addition of a mitogen-activated protein kinase kinase inhibitor to rapamycin or rapamycin plus PTK inhibitor further increases efficacy. Our results suggest that simultaneous targeting of more than one signaling pathway required by leukemogenic PTKs may improve the treatment of primary and relapsed CML and/or acute myelogenous leukemia caused by FLT3 mutations. Similar strategies may be useful for treating solid tumors associated with mutant and/or overexpressed PTKs.

Antibiotics, Antineoplastic↗

Dietary intake of Cruciferous vegetables, Glutathione S-transferase (GST) polymorphisms and lung cancer risk in a Caucasian population.

OBJECTIVE: To evaluate possible interactions between dietary intake of cruciferous vegetables and the glutathione s-transferase mu and theta (GSTM1 and GSTT1) genotypes in lung cancer risk. METHODS: Hospital-based case-control study of 716 Caucasian lung cancer cases and 939 spouse and friend controls conducted in Boston, Massachussetts between 1992 and 2000. Dietary intake was collected through a food frequency questionnaire and blood was obtained for genotyping. Logistic regression models were adjusted for age, gender, total calories and smoking variables. RESULTS: Higher intakes of cruciferous vegetables reduced lung cancer risk among GSTM1 present individuals (odds ratio (OR)highest versus lowest tertile = 0.61, 95% confidence interval (CI) = 0.39-0.95) but not among GSTM1 null individuals (OR(highest versus lowest tertile) = 1.15, 95% CI = 0.78-1.68). We observed statistically significant interactions between GSTM1 and cruciferous vegetable intake overall (likelihood ratio test (LRT): p = 0.05) and among current smokers (LRT: p = 0.01). No significant interactions were observed for GSTT1 or the combined GSTM1/T1 genotype. CONCLUSIONS: In our study, higher cruciferous vegetable intake reduced lung cancer risk only among individuals with the GSTM1 present genotype. Our findings differed from prior studies that specifically assessed isothiocyanates found in cruciferous vegetables or evaluated Asian study populations with higher levels of cruciferous vegetable consumption.

Aged↗

Oral fludarabine has significant activity in patients with previously untreated chronic lymphocytic leukemia, and leads to increased STAT1 levels in vivo.

Fifteen patients with previously untreated chronic lymphocytic leukemia (CLL) were treated with oral fludarabine. Toxicities were mainly hematologic, and the response rate was 80%. To assess the effect of fludarabine on the transcription factor STAT1, blood samples obtained on study entry were treated in vitro with fludarabine for 24 h, and the majority of samples displayed an expected decrease in STAT1. To determine whether similar changes occurred in vivo, we developed a flow cytometric assay to quantitate STAT1 levels. On completion of fludarabine cycle 1, CLL cells showed increased STAT1 in the majority of patients, in contrast to the in vitro findings. This may reflect a survival advantage for cells that express high levels of STAT1. In conclusion, oral fludarabine is highly active and merits further investigation in previously untreated patients with CLL. Larger studies are indicated to determine optimal timing of STAT1 assessment, and if changes in STAT1 represent an in vivo indicator of response to purine analog therapy.

Administration, Oral↗