bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lack of Influence of Rituximab and CNS Directed Prophylactic Therapy on CNS Relapse in High-Risk Diffuse Large B Cell Lymphoma
Authors: Yellu Mahender , Malek Ehsan , Thavalathil Berry , Latif Tahir 
Published: October 2019

Abstract
Background/method: Central nervous system (CNS) relapse in patients with diffuse large B-cell lymphoma (DLBCL) although uncommon, can be devastating. Conflicting reports have been published regarding the reduction in incidence of CNS relapse in post-rituximabera.We retrospectively identified all the patients with DLBCL who has received rituximab-based chemotherapy at initial presentation in our institute between 2004 and 2014. Patients were divided into two groups, ‘high risk’ group and ‘standard risk’ group, based on following definition. High risk group will have at least one of the following risk factors 1) LDH ≥ 650 U/L 2) Age adjusted International Prognostic Index (IPI) of ≥ 4 3) Involvement of > 1 extra nodal site 4) Involvement of testis 5) Breast 6) Bones 7) Kidneys 8) Adrenal glands 9) Retroperitoneal lymph nodes 10) Para-meninges or 11) Bone marrow. Patients without any of these risk factors were deemed standard risk. Descriptive statistics were used to analyze the incidence of CNS relapse, patient and disease characteristics. Historically reported incidence rates were used for comparison.
Results:One hundred and forty two consecutive patients with DLBCL were included in our study. One hundred and twenty two patients received rituximab-based therapy at the initial diagnosis. Forty-nine patients (40%) met the criteria for ‘high risk’ based on the above definition. Seventy-three patients (60%) qualified for standard risk group. Standard risk group received no CNS directed prophylaxis and none of these patients had CNS relapses. Thirty-one of 49 ‘high risk’ patients received CNS prophylaxis, mainly intrathecal methotrexate. Total 5 patients (4.09%) developed CNS relapse. CNS relapse in high-risk group was 10.2% (5/49). Median age at diagnosis in patients with CNS relapse was 53 years. Median time to relapse was 8.76 months. Median survival after the CNS relapse was 9.16 months. Four out of 5 patients received CNS prophylaxis with intrathecal methotrexate or systemic methotrexate or systemic cytarabine or a combination of them. Average number of doses of prophylaxis received by each patient was 3.2 (range 1-7). Only one patient who developed CNS relapse did not receive any CNS directed therapy as prophylaxis.
Conclusion:No significant reduction in the incidence of CNS relapse was noted with upfront use of rituximab. Our study confirms that majority of the DLBCL patients do not need CNS directed therapy. For high risk DLBCL patients, we not only need to develop better predictive markers for CNS relapse but also need better CNS directed therapies to prevent this fatal complication of highly curable disease.

Disclosures
No relevant conflicts of interest to declare.
Outcomes of HCV-Positive Patients with Lymphoma Treated with Rituximab-Containing Therapies
Authors: Rodgers Corica Marie , Shastri Aditi , Battini Ramakrishna 
Published: October 2019

Abstract
Introduction: The impact that hepatitis C virus (HCV) infection has on the clinical outcome of patients with lymphoma treated with rituximab-containing therapies is uncertain. Rituximab has improved outcomes in patients with aggressive lymphomas however the prognostic value of rituximab in HCV infected patients has not been well established. It has been shown that reactivation is a common complication in patients with hepatitis B treated with rituximab. It is possible that patients with hepatitis C also develop reactivation with rituximab resulting in worsening liver function and a poor clinical outcome. A prior Japanese study showed that HCV-positive patients with diffuse large B-cell lymphoma have a high incidence of severe hepatic toxicity (Ennishi, D., Maeda, Y., et al. 2010). In this study we wanted to further analyze this idea and see if it is applicable to American population with hepatitis C and lymphoma receiving rituximab-containing therapies.
Methods: We collected data from patients who were HCV-positive with lymphoma treated with rituximab between 2003 and 2014 at Montefiore Medical Center. Patients were included who were over 18 years old with a positive HCV test prior to treatment. Data was analyzed using statistical software Stata (version 12.0, StataCorp LP, College Station, TX, USA).
Results: A total of 33 HCV-positive patients with lymphoma were included. Most of these patients (82%) had diffuse large B-cell lymphoma (DLBCL). Of the 33 patients, 24 (73%) showed worsening liver function after starting Rituximab containing therapy. Hepatitis C viral load before and after the treatment was documented for 8 patients. 5 of these 8 patients had clear reactivation of hepatitis C with rising hepatitis C viral load. All of these 5 patients noted with worsening of liver function tests. These patients received an average of 2 doses of Rituximab before having the rise in liver function tests (LFTs). Also, the median duration to see a rise in liver transaminases was at 2.5 months with the peak level in liver enzymes observed at 4 months after starting rituximab.
Conclusion: These results show that patients with HCV infection have a high incidence of hepatic toxicity with rituximab. Some of these patients also showed evidence of reactivation with increased hepatitis C viral load. Further studies need to be done to determine if addition of new oral hepatitis C treatments like Sofosbuvir to the chemotherapy would change the course of viral reactivation and hepatic toxicity. These patients may need closer hepatic monitoring during and after treatment with rituximab.
References:
Ennishi, D., Maeda, Y., et al. (2010). “Hepatic toxicity and prognosis in hepatitis C virus-infected patients with diffuse large B-cell lymphoma treated with rituximab-containing chemotherapy regimens: a Japanese multicenter analysis.” Blood 116(24): 5119-25

Disclosures
No relevant conflicts of interest to declare.
Relapsed or Refractory Burkitt Lymphoma in Children and Adolescents after BFM-Type First-Line Therapy - a BFM Group Report
Authors: Woessmann Wilhelm , Zimmermann Martin , Burkhardt Birgit , Meinhardt Andrea , Rosenbusch Christine , Vaillant Vera , Oschlies Ilske , Klapper Wolfram , Niggli Felix , Attarbaschi Andishe , Mann Georg , Schrappe Martin , Reiter Alfred 
Published: October 2019

Abstract
Introduction: Current effective front-line therapies for Burkitt lymphoma leave few patients with relapsed or refractory disease. The objective of this analysis was to evaluate outcome, re-induction and SCT -approaches as well as risk factors in children and adolescents with progression or relapse of a Burkitt lymphoma/leukemia after current BFM-type first-line therapy.
Patients and Methods: We analyzed a population-based cohort of 145 children with relapsed Burkitt lymphoma/leukemia after BFM-type first-line therapy between 1986 and 2013. Recommended salvage until 2000 was BFM-type re-induction chemotherapy followed by autologous hematopoietic stem cell transplantation (SCT). From 2001 on different re-inductions were used, Rituximab was applied in relapse and both autologous and allogeneic SCT were performed.
Results:With a median follow-up of 8.2 (2.7-9.6) years, the 4-year survival after first relapse was 15±3%. Survival significantly improved for patients with relapse/progression after 2000 (until 2000, n=82: 11±3%, 2001 and later, n=63: 21±5%, p=.004) so that further risk factor analyses were performed on these 63 patients: Almost all patients with progression during front-line therapy (21/22), progression during re-induction (26/27), those not reaching CR before SCT (14/15) or not receiving rituximab during re-induction (9/9) died. Survival of 12 patients relapsing after initial therapy for low risk disease (R1/R2) was 42±14% compared to 16±5% for 51 patients relapsing after R3/R4-therapy (p=.02). CNS involvement could not be confirmed as statistically significant risk factor. Re-induction by CC (25 patients), ICE (8 patients), ICI (6 patients) or other regimen (11 patients) was followed by SCT in 31 patients (autologous, 18 patients; allogeneic, 13 patients). These approaches were associated with comparable survival of 16±5%. Two centers used a strategy of two to three courses of intensive continuous-infusion re-induction based on Vincristin (or Paclitaxel), Ifosfamide, Carboplatin, Idarubicine, Rituximab and intrathecal triple therapy without complete hematological regeneration between courses followed by allogeneic SCT. Survival of 8 patients treated this way was 63±17% (p=.034 as compared to the survival with other regimen). A center-effect may confound.
Conclusion: Patients with relapsed Burkitt lymphoma/leukemia still have a poor chance to survive after current effective front-line therapy. Time-condensed continuous-infusion re-induction with CD20-antibodies followed by SCT might form the basis for trials testing new drugs.

Disclosures
Off Label Use: Most chemotherapy drugs used for relapsed Burkitt lymphoma as well as Rituximab are not licenced for children and adolescents..
Connective Tissue Growth Factor Induces Anti-Apoptotic Factors in Chronic Myeloid Leukemia Stem Cells
Authors: Chang Patrick C , Low-Marchelli Janine M , Shahbandi Ashkan , Goff Daniel J , Jamieson Catriona 
Published: October 2019

Abstract
Chronic Myeloid Leukemia (CML) is a progressive hematopoietic malignancy where expression of the oncogenic fusion protein BCR-ABL1 in leukemia stem cells (LSCs) prevents the proper differentiation of myeloid progenitor populations, leading to accumulation of undifferentiated blasts. Current treatments target BCR-ABL1 with tyrosine kinase inhibitors (TKIs). Though effective if administered continuously, TKIs generally fail to eradicate the bone marrow niche-residing LSCs responsible for patient relapse or progression of CML to its terminal stage, Blast Crisis (BC), as evidenced by the high molecular relapse rate following TKI discontinuation. Previous studies performed by ourselves and others show that BC progenitors (CD34+CD38+Lin-) exhibit stem-like behaviors, such as quiescence, self-renewal, and induction of pro-survival gene expression through alternative splicing of BCL2 family members, and thus behave like LSCs. Notably, BC CML LSCs co-cultured on LSC (SL/M2) supportive stroma are resistant to TKIs compared to culturing the cells alone, indicating a role of the extracellular matrix (ECM) in promoting LSC survival. We performed RNA-seq and qRT-PCR of CD34+CD38+Lin- progenitor cells in CML patient samples and found a significant increase in CTGF (Connective Tissue Growth Factor) expression in BC CML versus chronic phase (CP). Interestingly, CTGF is an ECM protein that enhances cell adhesion and has been shown to predict therapeutic resistance in cancers, such as acute lymphoblastic leukemia (ALL). Lentiviral overexpression of CTGF in a CML cell line K562 and CD34+ CP CML patient samples caused proliferation and a decrease in apoptosis markers (cleaved caspase-3), as measured by FACS analysis. Moreover, qRT-PCR analysis of mRNA indicated an increase in pro-survival BCL2 family gene expression. These changes were not observed in normal CD34+ cord blood cells. Currently, lentiviral CTGF transduction of CP CML followed by transplantation into RAG2-/-gc-/- and NSG-S mice will be used to determine the effects of CTGF on LSC maintenance in vivo. In conclusion, CTGF promotes CML LSC survival in vitro and thus could be a key factor in BC transformation and TKI resistance.

Disclosures
Jamieson: J&J, Roche: Research Funding.
KLF4 Regulates Self-Renewal of Leukemic Stem Cells in Chronic Myeloid Leukemia By Repressing Gbl Expression and Altering mTORC2 Activity
Authors: Park Chun Shik , Shen Ye , Yamada Takeshi , Suppipat Koramit , Puppi Monica , Lacorazza Daniel 
Published: October 2019

Abstract
Tyrosine kinase inhibitors (TKIs) are the standard treatment for eradicating BCR-ABL-positive progenitor cells in chronic myeloid leukemia (CML); however, disease often relapses upon drug discontinuation because TKIs do not effectively eliminate leukemic stem cells (LSC). The development of novel strategies aimed at eradicating LSC without harming normal hematopoietic stem cells (HSC) is essential for the cure of CML patients. The generation of LSC-directed therapy relies on the identification of novel molecular pathways that selectively regulate LSC function independent of BCR-ABL. The Krüppel-like factor 4(KLF4) is a transcription factor that can either activate or repress gene transcription acting as an oncogene or a tumor suppressor depending on the cellular context. Analysis of a published dataset from chronic phase CML patients revealed elevated levels of KLF4 in LSC compared to progenitor cells indicating that KLF4 is likely implicated in LSC regulation. To study the role of KLF4 in LSC function, we used a CML mouse model combining somatic deletion of the Klf4 gene and retroviral transduction and transplantation of HSC. In contrast to mice receiving BCR-ABL-transduced Klf4fl/fl HSC that developed and succumbed to CML, mice transplanted with BCR-ABL-transduced Klf4Δ/Δ (Klf4fl/fl Vav-iCre+) HSC showed a progressive loss of leukemia despite an initial expansion of myeloid leukemic cells, which led to increased overall survival. This inability to sustain CML in the absence of KLF4 was caused by attrition of LSC in bone marrow and the spleen. Furthermore, deletion of KLF4 impaired the ability of LSC to recapitulate leukemia in secondary recipients suggesting a loss of self-renewal capacity. In contrast to LSC, KLF4 deletion led to increased self-renewal of normal HSC assessed by serial competitive transplantation. To identify KLF4 target genes involved in LSC self-renewal, we performed a global gene expression analysis using Klf4Δ/Δ LSC purified by cell sorting from leukemic mice. Analysis of gene expression in Klf4Δ/Δ LSC revealed significant upregulation of GβL, a component of mTOR complexes. Finally, we identified that KLF4 binds to GβL promoter by Chip-Seq analysis and that silencing resulted in inhibition of mTORC2 but not mTORC1 activity in 32D-BCR-ABL-positive CML cells. Our findings suggest that KLF4 transcriptionally represses GβL expression in LSC and that mTORC2 inhibition has the potential to completely eradicate LSC and induce treatment-free remission.

Disclosures
No relevant conflicts of interest to declare.
Xenograft Models of Multiple Myeloma Reveal That PU.1 Serves As a Tumor Suppressor for Multiple Myeloma
Authors: Nishimura Nao , Endo Shinya , Ueno Niina , Ueno Shikiko , Yuki Hiromichi , Hata Hiroyuki , Mitsuya Hiroaki , Okuno Yutaka 
Published: October 2019

Abstract
PU.1 is an essential transcription factor for hematopoiesis and important for differentiation of both myeloid and lymphoid lineages. In mice conditionally knocked-out of 3.4 kb length of the enhancer region located in14 kb 5’ upstream of the PU.1 gene (URE), PU.1 is down-regulated in myeloid cells and B cells by 20% of that of wild type, and such mice develop acute myeloid leukemia and CLL-like diseases. These data strongly suggest that PU.1 has tumor suppressor activity in hematopoietic cells. We previously reported that human PU.1 is down-regulated in the majority of myeloma cell lines through the methylation of the promoter and the 17 kb upstream enhancer region (URE) of the PU.1 gene that is homologous to that in 14 kb 5’ upstream of the murine PU.1 gene. Conditionally expressed PU.1 with tet-off system induced cell growth arrest and apoptosis in two myeloma cell lines, KMS12PE and U266, suggesting that the down-regulation of PU.1 is necessary for myeloma cell growth. We have also reported that PU.1 is expressed in normal plasma cells and in contrast, PU.1 is down-regulated in primary myeloma cells from a subset of myeloma patients, who appear to have poor prognosis.
In the present study, to test whether PU.1 has tumor suppressor activity in vivo, we generated xenograft mouse models. 0.6 - 1 x 107 KMS12PE cells were subcutaneously injected in 16 immunodeficient mice (Rag2-/- Jak3-/- bulb/c). The mice were then administered doxycycline through drinking water. Half of the mice (N=8) stopped taking doxycycline when the tumor sizes reached 1 cm in diameter, whereas the other half (N=8) kept taking doxycycline. Although the tumors in the mice taking doxycycline continued to grow, the tumor growth in the mice not taking doxycycline significantly slowed down. Flow cytometry analysis of the tumors in the mice that stopped taking doxycycline revealed that the cells from the tumor had completely lost PU.1 expression. Moreover, when U266 cells conditionally expressing PU.1 were subcutaneously injected to another 10 mice and the same experiment was conducted, although the tumors in the mice taking doxycycline (N=5) kept growing, the tumors in the mice not taking doxycycline (N=5), did not grow any further. The present data suggest that PU.1 serves as a tumor a suppressor in the multiple myeloma cell lines as examined in vivo.

Disclosures
No relevant conflicts of interest to declare.
Spi-1/PU.1 Accelerates Replication Fork Elongation through PP1a Phosphatase-Associated Dephosphorylation of CHK1 in Erythroleukemic Cells
Authors: Rimmelé Pauline , Guervilly Jean-Hugues , Rosselli Filippo , Moreau-Gachelin Françoise , Guillouf Christel 
Published: October 2019

Abstract
The multistage process of leukemic formation is driven by the progressive acquisition of somatic mutations. Replication stress creates genomic instability in mammals. Oncogenes and tumor suppressors trigger a replicative stress, that will consequently participates to the progression of cancer partly through this increased genetic instability. Thus, determining how cells cope with replicative stress should help understanding leukemogenesis and lead to the identification of new targets for antitumor treatments. Using a multistep leukemia model driven by Spi-1/PU.1 overexpression, we investigated the relationship between DNA replication and cancer progression. We have previously identified that the constitutive overexpression of the oncogenic transcription factor Spi-1/PU.1 is associated with an increased speed of DNA chain elongation favoring genetic instability without inducing DNA strand breaks. The Spi-1-induced replicative stress is peculiar because, in contrast to most of stress triggered by oncogenes or tumor suppressor, it is associated with an increase fork progression speed instead of alteration in the program of origin firing.
Here, we bring evidence that the S phase checkpoint protein, CHK1, is maintained in the inactive dephosphorylated form in Spi-1/PU.1 overexpressing pre-leukemic cells inducing and/or maintaining the observed high speed of DNA chain elongation. CHK1 under-phosphorylation is not due to defects in ATR signaling, its main regulator. Moreover, pharmacological inhibition of the kinases, ATM and DNA-PK, did not decrease CHK1 phosphorylation in the preleukemic cells overexpressing Spi-1. These findings are not consistent with an involvement of DNA damage response kinases in Spi-1-mediated modulation of CHK1 phosphorylation.We found that PP1a expression is increased in Spi-1/PU.1 overexpressing pre-leukemic cells compared to cells in which Spi-1/PU.1 was down-regulated. Two functional assays bring arguments that PP1 activity mediates the Spi-1/PU.1 effect on CHK1 dephosphorylation. Indeed, inhibition of PP1activity in cells overexpressing Spi-1 promoted the phosphorylation of CHK1, while the overexpression of PP1a led to the loss of a correlation between CHK1 phosphorylation and Spi-1 expression. In addition, PP1a inhibition and overexpression, not only acted on the CHK1 phosphorylation status controlled by Spi-1 but also inversely modified the progression of replication. Altogether, these results support the existence of a pathway linking Spi-1/PU.1 expression to acceleration of DNA replication via a PP1-mediated control of CHK1 phosphorylation in the pre-leukemic cells. These results identified a new pathway by which an oncogene influences replicative stress and favors the leukemic progression by fostering the incidence of genomic instability.

Disclosures
No relevant conflicts of interest to declare.
Flow-Cytometry MRD Evaluation in Children with ALL; Can MRD Level on Day 33 Serve As a Surrogate Marker for Relapse?
Authors: Ampatzidou Maria , Paterakis George , Tsitsikas Konstantinos , Papadhimitriou Stephanos I. , Papadakis Vassilios , Vasdekis Vassilios , Petrikkos Loizos , Polychronopoulou Sophia 
Published: October 2019

Abstract
Treatment-response assessment via quantification of MRD has become a corner-stone for risk stratification in childhood ALL. Although MRD has been shown to retain independent prognostic significance, the relationship with other prognostic variables has been incompletely explored. Moreover, determination of the most reliable treatment time-point for FCM-MRD evaluation that would serve as the best surrogate marker in predicting relapse, is still an issue of debate. To determine the utility of sequential measurements of FCM-MRD, with specific emphasis on day 33 and its correlation with known prognostic factors and outcome, we retrospectively analyzed the results of FCM-MRD study/data of 825 bone marrow samples of 133 children with ALL, at different treatment time-points, during induction and early consolidation (days 15, 33, 78, week 22-24, at start and at the end of maintenance therapy). All patients were homogeneously treated on BFM-based protocols and prognostic groups were defined by sex, WBC, prednisone response, risk-group allocation, immunophenotype and ETV6/RUNX1-presence. We investigated: a) the relationship between relapse probability and known prognostic factors like age, sex, WBC, immunophenotype, prednisone-response, ETV6/RUNX1 translocation, CDKN2A/2B deletion, hyperdiploidy, protocol risk-group, MRD(constant variable) and MRD positivity(≥0.1% vs <0.1%)(Kaplan-Meier and lïgrank test), b) the correlation between MRD(+) and outcome (OS and EFS, Kaplan-Meier). Additionally, multivariable Cox-models were used to determine the impact of MRD and WBC, sex, age, prednisone-response, on OS and EFS.
Patients with MRD≥0.1% at the end of induction (day 33) were estimated with 5-year RFS rates of only 60.0±12.8%, compared to MRD low(<0.1%)/negative patients that enjoyed superior 5-year RFS rates of 91.3±3.0%. Both days 15 and 33 of FCM-MRD positivity maintained a significant prognostic impact on the incidence of relapse within all subgroups. MRD(+)d15 and MRD(+)d33 detection combined, appeared to have a statistically significant impact on survival probability (RFS 65.9%±10.6, p<0.001). Additionally, FCM-MRD on day 33 was notably more strongly associated with used prognostic factors, while we were able to demonstrate that FCM-MRD log-reduction rates between days 15 and 33 can also be added as an important relapse prediction marker, apart from absolute MRD quantifications.
In our study, MRD(+)d15 and MRD(+)d33 in combination, strongly and statistically significant correlated with survival probability. Additionally, we propose the FCM-MRD log-reduction rate between days 15 and 33 and end-induction evaluation(day 33) as better predictors of survival and relapse probability, than only day 15 FCM-MRD estimations.
Figure 1 Figure 1.

Disclosures
No relevant conflicts of interest to declare.