ALBERT

Beschreibung: Lung cancer development relies on cell proliferation and migration, which in turn requires interaction with extracellular matrix (ECM) components such as glycosaminoglycans (GAGs). The mechanisms through which GAGs regulate cancer cell functions are not fully understood but they are, in part, mediated by controlled interactions with cytokines and growth factors (GFs). In order to mechanistically understand the effect of the degree of sulfation (DS) of GAGs on lung adenocarcinoma (LUAD) cells, we synthesized sulfated alginate (AlgSulf) as sulfated GAG mimics with DS = 0.0, 0.8, 2.0, and 2.7. Human (H1792) and mouse (MDA-F471) LUAD cell lines were treated with AlgSulf of various DSs at two concentrations 10 and 100 µg/mL and their anti-tumor properties were assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), trypan blue exclusion, and wound healing assays for 2D models and sphere formation assay for the 3D model. The proliferation and number of live MDA-F471 cells at the concentration of 100 µg/mL decreased significantly with the increase in the DS of biomimetic GAGs. In addition, the increase in the DS of biomimetic GAGs decreased cell migration (p 〈 0.001 for DS = 2.0 and 2.7 compared to control) and decreased the diameter and number of spheres formed (p 〈 0.001). The increased DS of biomimetic GAGs attenuated the expression of cancer stem cell (CSC)/progenitor markers in the 3D cultures. In conclusion, GAG-mimetic AlgSulf with increased DS exhibit enhanced anti-proliferative and migratory properties while also reducing growth of KRAS-mutant LUAD spheres in vitro. We suggest that these anti-tumor effects by GAG-mimetic AlgSulf are possibly due to differential binding to GFs and consequential decreased cell stemness. AlgSulf may be suitable for applications in cancer therapy after further in vivo validation.

Beschreibung: Abstract 3917 Treatment with the anti-CD20 monoclonal antibody rituximab (RTX) has become the standard-of-care for the treatment of B-cell non-Hodgkin lymphoma (NHL). Despite revolutionizing NHL therapy, many patients demonstrate resistance de novo or develop resistance to RTX following treatment with RTX-containing regimens and/or RTX-based maintenance schedules. Ofatumumab (OFA) is a new 2nd-generation CD20 mAb targeting a novel membrane-proximal epitope on the CD20 antigen. OFA has been FDA-approved for the treatment of fludarabine- and alemtuzumab-refractory CLL and is being evaluated in several clinical trials in NHL. To better define OFA's activity, we conducted pre-clinical studies comparing OFA vs. RTX in a panel of RSCL, RRCL, primary lymphoma cells (n=10), and in a lymphoma xenograft model. Antibody-dependant cellular cytotoxicity (ADCC) and complement dependent cytotoxicity (CDC) assays were performed to evaluate differences in activity between RTX and OFA. Lymphoma cells were labeled with 51Cr prior to incubation with RTX or OFA (1 or 10 mg/ml) plus effector cells or human serum respectively. 51Cr-release was measured and the percentage of lysis was calculated. In addition, we evaluated the effect of OFA in the cytotoxic effects of chemotherapy agents (doxorubicin, cisplatin and vincristine) and correlated OFA anti-tumor activity to biomarkers known to affect RTX activity (i.e. CD20, CD55, and CD59 surface expression) using qualitative and quantitative flow cytometry. Competitive binding assays were performed using fluorescent-labeled RTX or OFA. OFA was more potent than RTX in elucidating effective CDC at the doses tested not only in RSCL, but also in all RRCL and in primary tumor cells derived from patients with B-cell lymphoma. OFA and RTX were equally effective in ADCC assays. In RSCL and RRCL, there was a linear decrease in sensitivity to RTX (as evaluated by CDC) with decreasing CD20 expression; in contrast, OFA maintained activity even at the lowest levels of CD20 expression. Furthermore, OFA was active despite high levels of CD59 and CD55. OFA had a higher affinity for CD20 than RTX in RSCL. Pre-incubation of RSCL and RRCL with OFA enhanced the anti-tumor activity of chemotherapy agents as determined by alamar blue reduction. Severe combined immunodeficiency (SCID) mice were inoculated via tail vein with Raji cells (day 0) and assigned to observation versus 4 doses of either OFA or RTX (1 or 10mg/kg/dose). The end point of the study was overall survival. Statistical analysis was performed with Kaplan-Meier survival curves and P values calculated by log-rank test. OFA was more effective in controlling in vivo lymphoma growth than RTX. The median survival for animals treated with OFA (1 or 10mg/kg/dose) [73 days and 78 days] was longer than those treated with RTX [56 days and 61 days] (P=0.04 and P=0.04 respectively). Our data suggest that OFA is more potent than RTX not only in RTX-sensitive but also in RTX-resistant models and potentiates the anti-tumor activity of chemotherapy agents commonly used in the treatment of B-cell NHL. We are continuing our research into defining the mechanisms by which OFA increases the lymphoma cell sensitivity threshold to chemotherapy agents and to novel target-specific small molecule inhibitors. Disclosures: Barth: Genmab: Research Funding. Hernandez-Ilizaliturri:Genmab: Research Funding. Mavis:Genmab: Research Funding. Gibbs:Genmab: Research Funding. Deeb:Genmab: Research Funding. Czuczman:Genmab: Research Funding.

Beschreibung: Abstract 3939 The use of proteasome inhibitors such as bortezomib (BTZ) has generated much excitement as a potential therapeutic approach capable of effectively treating resistant/refractory lymphoid neoplasm. Clinical outcomes in multiple myeloma and relapsed mantle cell lymphoma demonstrate that these novel agents can overcome resistance demonstrated by a lack of antitumor activity to traditional salvage chemotherapeutic agents. Our group of investigators have demonstrated that proteasome inhibition using BTZ can increase pro-apoptotic Bcl-2 family member expression and restore chemotherapy sensitivity in rituximab-chemotherapy resistant cell lines (RRCL). To further develop therapeutic strategies targeting the proteasome system, we studied the anti-tumor activity and mechanisms-of-action of MLN2238, a novel irreversible proteasome inhibitor, in pre-clinical lymphoma models. Experiments were conducted in rituximab-chemotherapy sensitive cell lines (RSCL), RRCL, and in tumor cells derived from patients with de novo or relapsed/refractory B-cell lymphoma. Cells were exposed in vitro and/or ex vivo to escalating doses of MLN2238 or BTZ (0.1-10nM) +/− caspase inhibitors (zVAD-fmk or Q-VD-OPh) for 24, 48 and 72h. Differences in mitochondrial potential and cell proliferation were determined by alamar blue reduction using a kinetic assay; changes in ATP content (apoptosis) were determined using the Cell Titer Glow assay. Effects on cell cycle were analyzed by the FASCan DNA method. In addition, lymphoma cells were exposed to MLN2238 or BTZ +/− doxorubicin, gemcitabine or paclitaxel and cell viability was evaluated as described above. In vitro, MLN2238 exhibited more potent concentration- and time-dependent cytotoxicity and inhibition of cell proliferation in RSCL, RRCL, as well as primary lymphoma cells than BTZ. In vitro exposure of RSCL and RRCL to MLN2238 potentiated the cytotoxic effects of gemcitabine, doxorubicin, and paclitaxel and overcame the acquired resistance to chemotherapy drugs in RRCL in a dose-dependent manner. Co-incubation of RSCL with bortezomib, or MLN2232 and either pan-caspase inhibitor led to a significant decrease in BTZ- or MLN2232-induced cell death. In contrast, neither zVAD-fmk nor Q-VD-OPh was capable of blocking BTZ- or MLN2232-induced cell death of RRCL. Our data suggest that BTZ and MLN2238 are also capable of inducing caspase-independent cell death in RRCL. To this regard, we found differences that RRCL are more likely to be in S phase in resting conditions when compared to RSCL. In vitro exposure of RRCL cells to MLN2232 (and to a much lesser degree BTZ) reduced RRCL S-phase and induced arrest at G2/M phase. Collectively, these data suggest that MLN2238 is a potent proteasome inhibitor active in rituximab-chemotherapy sensitive or resistant cell models and potentiates the anti-tumor activity of chemotherapy agents. MLN2232 appears to posses several mechanisms-of-action (induction of apoptosis and/or cell cycle arrest) and has the potential of becoming a novel and potent target-specific therapeutic agent in the future treatment of therapy-resistant B-cell lymphoma. (Research, in part, supported by a NIH grant R01 CA136907-01A1 awarded to Roswell Park Cancer Institute). Disclosures: No relevant conflicts of interest to declare.

Beschreibung: Abstract 5073 BCL6 proto-oncogene is one of the markers for germinal center origin in DLBCL and encodes a transcriptional repressor factor. Mutation or translocation affecting this proto-oncogene has been implicated in the pathogenesis of certain subtypes of DLBCL. Studies using both gene expression profiling and immunohistochemistry (IHC) have demonstrated that BCL6 gene or Bcl-6 protein expression alone or in combination with other markers for germinal center origin predicts a favorable outcome in DLBCL. However, the prognostic significance of Bcl-6 has been challenged by the incorporation of rituximab into the standard chemotherapy regimens of DLBCL. To elucidate the prognostic value of Bcl-6 in patients treated with rituximab -based chemo-immunotherapy (R+CHOP or R+DA-EPOCH), we retrospectively evaluated the clinical outcomes of DLBCL patients treated at Roswell Park Cancer Institute (RPCI) between 1997 and 2008. De Novo DLBCL patients were identified using the RPCI tumor registry and pharmacy database. Demographic (age, race, sex), clinical (stage, IPI score, ECOG performance status, etc.) and pathological characteristics were obtained for each patient. A total of 242 consecutive DLBCL patients (89F/153M) were included in the study. The median age was 60 years (19-91). Using IHC, Bcl-6 expression was reported to be positive in 123/190 patients (64%) and Bcl-2 expression was detected in 86/125 patients (69%). Demographics and clinical characteristics such as Ann Arbor stage, international prognostic index (IPI) score, performance status (ECOG), and number of cycles of chemotherapy (Median number of cycles=6) were equally distributed between Bcl-6(+) and Bcl-6(-) DLBCL patients. Most patients received R+CHOP (86.4%) or R+ DA-EPOCH (13.6%). The complete response (CR) rate of the entire cohort was 77.7% and there was no difference between Bcl-6(+) and Bcl-6(-) DLBCL patients (P=0.22). After a median follow up of 3.9 years, significant differences in the PFS and OS were observed between Bcl-6(+) and Bcl-6(-) DLBCL. The 5yr-PFS of Bcl-6(+) DLBCL patients was superior to Bcl-6(-) DLBCL (66% vs. 42%, P=0.001). Similarly, the 5yr-OS was better in Bcl-6(+) than in Bcl-6(-) DLBCL patients (78% vs. 63%, P=0.023). A sub-group analysis of DLBCL patients with Bcl-6 and Bcl-2 testing by IHC studies (N=119) demonstrated that Bcl-6 expression was a strong positive predictor of PFS and OS in Bcl-2(-) DLBCL (P=0.002 and P=0.037 respectively). In Bcl-2(+) DLBCL, while Bcl-6 expression was associated with a longer PFS (39 vs. 13 months) and OS (68 vs. 42 months) than in Bcl-2(+)/Bcl-6(-) DLBCL, the difference was not statistically significant (P=0.107 and P=0.174 respectively). In conclusion, our data suggests that, the expression of Bcl-6 by IHC is associated with a better PFS and OS in patients with DLBCL treated with rituximab-chemotherapy in the front-line setting. The positive predictive value of Bcl-6 expression appears to be negatively affected by Bcl-2 over expression. In the post-rituximab era, Bcl-6 negative DLBCL represent a subgroup of DLBCL with poor clinical outcomes. Additional work should be done to determine if the clinical significance of bcl-6 expression is still valid in germinal center B cell like (GC) and non-GC subsets of DLBCL. There is a clinical and scientific need to understand, at the molecular level, differences between DLBCL subtypes and to develop novel treatment strategies targeting cellular pathways driving each particular subtype of DLBCL. Disclosures: No relevant conflicts of interest to declare.

Beschreibung: Background DLBCL is the most common type of non-Hodgkin lymphoma, which demonstrates morphologic, immunophenotypic, molecular, and clinical heterogeneity. Gene expression profiling studies define two molecular subtypes of DLBCL, namely germinal center B-cell-like (GCB) and activated B-cell-like (ABC) DLBCL. Hans' algorithm was developed to provide an immunohistochemical correlation to the molecular subtypes of DLBCL. In the pre and post-rituximab era, ABC subtype of DLBCL is known to demonstrate poor overall survival when compared to GCB subtype. In addition, relapsed or primary refractory DLBCL responds poorly to current therapeutic strategies. These findings underscore the necessity to identify novel therapeutic targets in DLBCL to achieve better clinical outcomes. Recent data suggests that CD30, a member of the tumor necrosis factor receptor family, is a potential therapeutic target in DLBCL. CD30 is widely expressed in classical Hodgkin lymphoma (cHL) and anaplastic large cell lymphoma (ALCL) thus serving as an attractive target of immunotherapy for cHL and ALCL. In this study we conducted a retrospective evaluation of CD30 expression in GCB and non-GCB DLBCL, treated at our Institution with standard front-line chemo-immunotherapy (i.e. R+CHOP or R+ DA-EPOCH). Materials and Methods We identified 60 patients with confirmed DLBCL for which archived formalin fixed paraffin embedded tissue was available in the form of a tissue micro-array (39 Cases) or diagnostic biopsy material (21 Cases). Immunohistochemical detection of CD30 was performed using routine methods (Biocare #PM031, ready to use aliquots). Demographic, clinical and pharmacological parameters were obtained for each patient. DLBCL cases were subtyped as GCB or non-GCB using immunohistochemistry-based Hans' algorithm. Membranous and Golgi pattern of CD30 expression in the tumor cells was designated as positive. Results 21 patients (48.8%) were classified as GCB, 22 patients (51.2%) non-GCB. CD30 expression was detected in 13.3% of all DLBCL patients. Differences in CD30 expression were noted between GCB- and non-GCB DLBCL. CD30 expression was detected in 9.5% and 23% of the GCB- and non-GCB DLBCL subtypes respectively. Demographics and clinical characteristics were equally distributed between GCB- and non-GCB and between CD30 positive or negative DLBCL. Patients received either R+CHOP (82%) or R+DA-EPOCH (18%). The complete response (CR) rate of the entire cohort was 67% and no differences were observed between GCB- or non-GCB DLBCL. CD30 (+) DLBCL had a higher CR (complete response) rate than CD30 (-) DLBCL (88% vs 63.4%). However, the numbers were too small to reach statistical significance. No significant differences were observed between CD30 (+) or (-) DLBCL in terms of progression free survival (PFS) (CD30[-]37m vs. CD30[+]16.5m, P =0.785) or overall survival (OS) (CD30[-]86m vs. CD30[+]57.4m, P =0.99). In contrast to previously reported by other investigators, there was no difference in the clinical outcome between GCB vs. non-GCB DLBCL treated with R+CHOP or R+DA-EPOCH. Conclusions Our data suggests that CD30 expression is more prevalent in non-GCB DLBCL patients based on our small cohort. While CD30 expression may not confer a prognostic value in newly diagnosed DLBCL (Table 1), routine testing for it may identify a group of patients that may benefit from CD30-targeted therapeutic strategies (i.e. antibody-drug conjugates) in the relapsed/refractory setting. (Research, in part, supported by The Eugene and Connie Corasanti Lymphoma Research Fund) Disclosures: Czuczman: Genetech, Onyx, Celgene, Astellas, Millennium, Mundipharma: Advisory Committees Other. Hernandez-Ilizaliturri:Seattle Genetics: Consultancy, Honoraria.

Beschreibung: Abstract 3130 DLBCL has been recognized as a heterogeneous disease varying in molecular biology and clinical outcome. The use of genetic expression profiling has led to the sub-classification of DLBCL into germinal center B-cell like (GCB) and non-germinal center B cell like (non-GCB) based on the cell of origin of the neoplastic B-cell. Immunohistochemistry (IHC) algorithms had been developed and validated to identify GCB or non-GCB DLBCL. Deregulation of Bcl-2 family member of proteins plays an important role in the development, progression, and prognosis of various subtypes of B-cell neoplasms, including DLBCL. Bcl-2 protein expression is a previously known negative prognostic indicator of clinical outcome in DLBCL treated with antracycline-containing combination chemotherapy (e.g. CHOP) in the past. In the post-rituximab (R) era (e.g. use of upfront R-CHOP), the negative prognostic value of Bcl-2 protein expression needs to be reevaluated to ensure its validity. To study the prognostic value of Bcl-2 in patients with either GCB or non-GCB DLBCL, we retrospectively analyzed differences in progression-free survival (PFS) and overall survival (OS) between Bcl-2+ and Bcl-2- de novo DLBCL (GCB or non-GCB subtypes). Using the RPCI tumor registry and pharmacy database, we identified 201 DLBCL patients treated with equivalent doses of rituximab and anthracycline-based therapy (i.e. R=CHOP or R+DA-EPOCH) at RPCI between 1997 and 2007. Demographic, clinical and pathological characteristics were obtained for each patient. Patients were classified into GCB or non-GCB DLBCL according to the Han's algorithm based on the expression of CD10, Bcl-6 and MUM-1. Bcl-2 was determined by IHC and was available for 101 patients. Using the Han's algorithm, fifty-three patients (26.4%) were classified as GCB, 54 patients (26.9%) non-GCB, and 94 patients (46.8%) could not be classified due to inadequate data/sample. Bcl-2 expression was detected in 67% and 73% of the GCB- and non-GCB DLBCL subtypes respectively. Demographics and clinical characteristics were equally distributed between GCB- and non-GCB DLBCL. Patients received either R+CHOP (90%) or R+DA-EPOCH (10%). The complete response (CR) rate of the entire cohort was 82.6% and no differences were observed between GCB- or non-GCB DLBCL (78.4% vs. 75.5%, P=0.73) or by Bcl-2 expression (+:72.5% vs. -:81.3%, P=0.35]. After a median follow up period of 74 months, significant differences were observed between Bcl-2 positive or negative and GCB or non-GCB DLBCL. GCB-DLBCL had a longer 5-yr PFS and 5-yr OS than non-GCB DLBCL (58.5% vs. 37%, P=0.026; 81.1% vs. 53.7% and, P=0.002; respectively). By itself, Bcl2 over-expression, had a negative impact in PFS (P=0.002) and OS (P=0.001) in R+CHOP/R+DA-EPOCH treated de novo DLBCL. The combined prognostic value of the Han's algorithm and Bcl-2 expression was also evaluated. Bcl-2 expression in the context of both GBC and non-GCB subtypes remains an unfavorable prognostic indicator for overall survival, with a more pronounced influence in the GCB-DLBCL phenotype (See table). Our data supports the predictive value of the Han's algorithm and Bcl-2 expression in DLBCL patients undergoing front-line chemo-immunotherapy. Bcl-2 expression is associated with a poor prognosis in GCB and non-GCB DLBCL. It is possible that intrinsic biological pathways involved in lymphomagenesis and/or “resistance” of these subtypes of DLBCL may play a role in their responsiveness to rituximab-based therapies and could be influenced by the net balance between pro- and anti-apoptotic proteins. Attempts to further delineate the biological heterogeneity of DLBCL may help identify subgroups of patients at high risk of resistance to chemo-immunotherapy and lead to the development of new therapeutic strategies. In conclusion, our data analysis confirms that the DLBCL immunophenotypes based on cell of origin and Bcl-2 status continues to have predictive significance on clinical outcomes in DLBCL in the rituximab era. Differences in clinical outcomes between GCB or non-GCB-DLBCL by Bcl-2 status Median PFS (months) Significance Median OS (months) Significance GCB-DLBCL Bcl-2 (-) NR *P = 0.016 NR *P =0.029 Bcl-2 (+) 39 83 Non-GCB DLBCL Bcl-2 (-) 49.8 NR Bcl-2 (+) 15 48 PFS = Progression free survival, OS = overall survival, GCB = germinal center B-cell, DLBCL = diffuse large B-cell lymphoma. * P values calculated by comparing GCB-DLBCL Bcl-2 (-) to the other groups Disclosures: No relevant conflicts of interest to declare.

Beschreibung: Abstract 3107 Poster Board III-44 Prior studies have demonstrated that hepatocyte growth factor (HGF) regulates proliferation and differentiation of normal hematopoietic progenitors. HGF activity occurs primarily via interactions with the c-met receptor, a tyrosine kinase receptor found on epithelial and some cancer cells. In solid tumors, HGF/c-met interactions mediate increased neoplastic invasion, metastases, and angiogenesis. However, in vitro, HGF has also been shown to mediate anti-tumor effects in leukemia cell line models. To better elucidate the role of HGF in acute leukemogenesis, we evaluated HGF and c-met gene expression in 91 normal karyotype acute myeloid leukemia (NK-AML) patient samples previously characterized for marrow angiogenesis (CD31+ microvessels), FLT-3/NPM-1 gene mutation, and pro-angiogenic factors and receptors (specifically vascular endothelial growth factors (VEGF-A and C) and their receptors). Median patient age was 66 years (range 21-87) with 49 women and 42 men. AML disease FAB subtypes M2 (37%) and M1 (36%) subtypes were most common. Median presenting white blood cell count (WBC) was 32,000/μL (range 0.43-555,000/μL) with marrow blasts of 70.6% (range 15-95.4%). Fourteen percent presented with extramedullary disease. Median OS was 9.4 months (95% CI 6.7 to 11.5 months), with median EFS of 8 months (95% CI 5.7 to 11.5 months) for all patients. Seventy-nine patients received cytarabine and anthracycline-based induction chemotherapy with 58% (n=46) achieving complete remission (CR). Marrow aspirate samples were evaluated by quantitative real-time polymerase chain reaction with levels expressed relative to normal bone marrow controls (set =1). We found that HGF gene expression was upregulated in most primary NK-AML patient samples, with 88% expressing higher HGF than normal bone marrow. Median HGF expression in AML samples was 7.73 fold higher than normal controls. Multivariate analysis including age, complete remission, marrow blasts, extramedullary disease, and expression of other angiogenic factors and receptors as covariables, showed high HGF expression to be significantly associated with both longer overall and event-free survival. Surprisingly, HGF gene expression was found to be negatively correlated with microvessel density and NPM-1 mutation and positively correlated with the VEGF receptor neuropilin-1 (NRP-1) which has been reported to function as co-mediator of HGF activity. No association between HGF and FLT-3 ITD mutation was noted. The majority of AML samples did not express the HGF receptor, c-met, suggesting that HGF function in AML occurs primarily via paracrine interactions with surrounding vascular and stromal cells and/or HGF/NRP-1 autocrine pathways. Further analysis confirmed no significant correlation between HGF and c-met gene expression in AML samples but did demonstrate a subset of NPM-1+ HGF+ AML samples (n=7) expressing high levels of both HGF and c-met (p=0.0005, r=0.96). To confirm whether HGF/c-met autocrine interactions contributed to leukemogenesis in these cells, we treated immunodeficient mice engrafted with an HGF+ c-met+ human AML cell line (HEL) with vehicle vs. a c-met tyrosine kinase inhibitor, and noted growth inhibitory effects following c-met blockade. Conclusions HGF gene expression was an independent predictive factor for improved clinical outcome and was associated with NRP-1 expression, lower microvessel density, and NPM-1 negative status in normal karyotype AML patients. A subset of AML samples was identified with high concordant HGF and c-met expression consistent with autocrine pathways. Inhibition of HGF/c-met interactions in a preclinical AML model exerted anti-tumor effects. Additional studies of the diverse roles of HGF in myeloid leukemogenesis are warranted. Disclosures No relevant conflicts of interest to declare.

Beschreibung: Abstract 4129 Several immunophenotypic subgroups within AML are associated with specific disease characteristics, e.g., CD19-positive AML is associated with t(8;21)(q22;q22) and CD56 expression is associated with adverse outcome. CD33 is a sialic acid-binding immunoglobulin-like lectin (Siglec) located on chromosome 19q13.3. It is highly expressed on early multilineage hematopoietic progenitors but absent from the pluripotent hematopoietic stem cells. It contains two tyrosine phosphorylation motifs whose phosphorylation depends on Src and is the target of gemtuzumab ozogamicin. We asked if lack of CD33 expression (

Beschreibung: The prognosis of adult NC pB-ALL has not improved over the last decade mainly because separation into distinct molecular subsets has been lacking. We conducted a proof-of-principle experiment to screen the genome of blasts from adult NC pB-ALL patients for novel genomic alterations using 19,000 bacterial artificial chromosomes (BAC) by array CGH and verified our results with gene expression profiling (GEP, Agilent oligonucleotide expression arrays) and fluorescent in situ hybridization (FISH) using the same BAC probes or commercially available probes if available. The median age at diagnosis of the 6 males and 4 females was 55 years; all were treated with a 5-drug induction regimen followed by intensive consolidation and maintenance regimens. Five achieved CR of whom 3 relapsed with complex karyotype; samples were available on 2 of the patients at relapse. Samples with 95% purity by sorting according to their immunophenotype pattern. Only one case had a normal CGH pattern. A decreased copy number of p16 was found in 4 of the 10 diagnostic samples; 3 on whom mRNA was available demonstrated a decreased p16 mRNA expression by GEP. In addition, a loss at 9p21.2 and a loss and a gain at 8q21.2 were detected in one sample each; those were verified by FISH. Copy number losses were also observed across multiple samples at 1p34–1p36, 4p16, 5p15.33, 8q24, 9q34, 10q26, 11q12–11q13, 12q24, 14q32, 17p, 19p13.3, 22q11, and 22q13. Copy number gains across multiple samples were observed at 15q11.2 and 18q21. Those are currently being verified by FISH. Comparison of samples at diagnosis and at relapse revealed a disparate molecular pattern. In summary, enriching samples by sorting from NC pB-ALL to be studied by CGH is feasible; normal chromosome pattern does not correlate with normal molecular pattern; and diagnostic and relapsed samples have a different molecular pattern. Our work on 10 patient samples at diagnosis and 2 at relapse demonstrates the feasibility to detect specific molecular aberrations in NC pB-ALL. Since attaining good quality metaphase cells in ALL is often suboptimal, this work suggests that array CGH can complement conventional cytogenetic analysis to better characterize NC pB-ALL by identifying cryptic copy number changes. Work on a larger number of samples is warranted to determine the prognostic significance of the aberrations detected herein.