The Dohner fluorescence in situ hybridization prognostic classification of chronic lymphocytic leukaemia (CLL): the CLL Research Consortium experience.

This study revisited the Dohner prognostic hierarchy in a cohort of 1585 well-documented patients with chronic lymphocytic leukaemia. The duration of both time to first treatment (TTFT) and overall survival (OS) were significantly longer than observed previously, and this is at least partly due to improved therapeutic options. Deletion 13q remains the most favourable prognostic group with median TTFT and OS from fluorescence in situ hybridization (FISH) testing of 72 months and >12 years, respectively. Deletion 11q had the poorest median TTFT (22 months) and 17p deletion the poorest median OS (5 years). The percentages of abnormal nuclei were significantly associated with differential TTFT for the trisomy 12, 13q and 17p deletion cohorts but not for the 11q deletion cohort. From the date of the first FISH study, patients with >85% 13q deletion nuclei had a notably shorter TTFT (24 months). Patients with ≤20% 17p deletion nuclei had longer median TTFT and OS from the date of the first FISH study (44 months and 11 years), and were more likely to be IGHV mutated.

Validation of ZAP-70 methylation and its relative significance in predicting outcome in chronic lymphocytic leukemia.

ZAP-70 methylation 223 nucleotides downstream of transcription start (CpG+223) predicts outcome in chronic lymphocytic leukemia (CLL), but its impact relative to CD38 and ZAP-70 expression or immunoglobulin heavy chain variable region (IGHV) status is uncertain. Additionally, standardizing ZAP-70 expression analysis has been unsuccessful. CpG+223 methylation was quantitatively determined in 295 untreated CLL cases using MassARRAY. Impact on clinical outcome vs CD38 and ZAP-70 expression and IGHV status was evaluated. Cases with low methylation (<20%) had significantly shortened time to first treatment (TT) and overall survival (OS) (P < .0001). For TT, low methylation defined a large subset of ZAP-70 protein-negative cases with significantly shortened TT (median, 8.0 vs 3.9 years for high vs low methylation; hazard ratio [HR] = 0.43; 95% confidence interval [CI], 0.25-0.74). Conversely, 16 ZAP-70 protein-positive cases with high methylation had poor outcome (median, 1.1 vs 2.3 years for high vs low methylation; HR = 1.62; 95% CI, 0.87-3.03). For OS, ZAP-70 methylation was the strongest risk factor; CD38 and ZAP-70 expression or IGHV status did not significantly improve OS prediction. A pyrosequencing assay was established that reproduced the MassARRAY data (κ coefficient > 0.90). Thus, ZAP-70 CpG+223 methylation represents a superior biomarker for TT and OS that can be feasibly measured, supporting its use in risk-stratifying CLL.

The TOKEn project: knowledge synthesis for in silico science.

OBJECTIVE: The conduct of investigational studies that involve large-scale data sets presents significant challenges related to the discovery and testing of novel hypotheses capable of supporting in silico discovery science. The use of what are known as Conceptual Knowledge Discovery in Databases (CKDD) methods provides a potential means of scaling hypothesis discovery and testing approaches for large data sets. Such methods enable the high-throughput generation and evaluation of knowledge-anchored relationships between complexes of variables found in targeted data sets. METHODS: The authors have conducted a multipart model formulation and validation process, focusing on the development of a methodological and technical approach to using CKDD to support hypothesis discovery for in silico science. The model the authors have developed is known as the Translational Ontology-anchored Knowledge Discovery Engine (TOKEn). This model utilizes a specific CKDD approach known as Constructive Induction to identify and prioritize potential hypotheses related to the meaningful semantic relationships between variables found in large-scale and heterogeneous biomedical data sets. RESULTS: The authors have verified and validated TOKEn in the context of a translational research data repository maintained by the NCI-funded Chronic Lymphocytic Leukemia Research Consortium. Such studies have shown that TOKEn is: (1) computationally tractable; and (2) able to generate valid and potentially useful hypotheses concerning relationships between phenotypic and biomolecular variables in that data collection. CONCLUSIONS: The TOKEn model represents a potentially useful and systematic approach to knowledge synthesis for in silico discovery science in the context of large-scale and multidimensional research data sets.

Self-administered, subcutaneous alemtuzumab to treat residual disease in patients with chronic lymphocytic leukemia.

BACKGROUND: Alemtuzumab is highly effective at treating chronic lymphocytic leukemia (CLL) in bone marrow, which is the usual site of residual disease after fludarabine-based treatment. Eliminating residual disease potentially is associated with longer remission and overall survival. The authors of this report evaluated the ability of subcutaneous alemtuzumab to treat residual disease. METHODS: Patients in partial remission (PR), nodular PR (nPR), or complete remission (CR) who had disease in bone marrow established by 2-color flow cytometry analysis were enrolled and received alemtuzumab 30 mg subcutaneously 3 times weekly for 4 weeks, and patients had the option to self-administer alemtuzumab. Responders were patients in PR who converted to an nPR or a CR, patients in nPR who converted to a CR, and patients in CR who had no evidence of disease on 2-color flow cytometry analysis after treatment. RESULTS: There were 31 patients enrolled, of whom 29 were evaluable, and there were 23 responders (4 of 4 patients who achieved a CR, 8 of 9 patients who achieved an nPR, and 11 of 16 patients who achieved a PR. Nonresponders had significantly lower plasma alemtuzumab levels at the end of treatment. Furthermore, higher plasma alemtuzumab levels at the end of treatment were correlated with a longer response duration. Compared with the results from an historic group that received intravenous alemtuzumab for residual disease, there was a trend toward a higher response rate but a shorter response duration with subcutaneous alemtuzumab. CONCLUSIONS: The current results demonstrated that self-administered, subcutaneous alemtuzumab was safe and active for residual disease and that plasma alemtuzumab levels and real-time minimal residual disease evaluation are important endpoints to monitor in future alemtuzumab consolidation trials.

Stimulation of chronic lymphocytic leukemia cells with CpG oligodeoxynucleotide gives consistent karyotypic results among laboratories: a CLL Research Consortium (CRC) Study.

Cytogenetic abnormalities are important prognostic indicators in CLL. Historically, only interphase cytogenetics was clinically useful in CLL, because traditional mitogens are not effective mitotic stimulants. Recently, CpG-oligodeoxynucleotide (ODN) stimulation has shown effectiveness in CLL cells. The CLL Research Consortium tested the effectiveness and reproducibility of CpG-ODN stimulation for detecting chromosomally abnormal clones by five laboratories. More clonal abnormalities were observed after culture of CLL cells with CpG-ODN than with the traditional pokeweed mitogen plus 12-O-tetradecanoylphorbol-13-acetate (PWM+TPA). All clonal abnormalities in PWM+TPA cultures were observed in CpG-ODN cultures, whereas CpG-ODN identified some clones not found by PWM+TPA. CpG-ODN stimulation of one normal control sample and 12 CLL samples showed that, excepting clones of del(13q) in low frequencies and one translocation, results in all five laboratories were consistent, and all abnormalities were concordant with FISH. Abnormal clones in CLL were more readily detected with CpG-ODN stimulation than with traditional B-cell mitogens. With CpG-ODN stimulation, abnormalities were reproducible among cytogenetic laboratories. CpG-ODN did not appear to induce aberrations in cell culture, but did enhance detection of abnormalities and complexity in CLL. Because karyotypic complexity is prognostic and is not detectable by standard FISH analyses, stimulation with CpG-ODN is useful for identifying this additional prognostic factor in CLL.

Standardization of fluorescence in situ hybridization studies on chronic lymphocytic leukemia (CLL) blood and marrow cells by the CLL Research Consortium.

Five laboratories in the Chronic Lymphocytic Leukemia (CLL) Research Consortium (CRC) investigated standardizing and pooling of fluorescence in situ hybridization (FISH) results as a collaborative research project. This investigation used fixed bone marrow and blood cells available from previous conventional cytogenetic or FISH studies in two pilot studies, a one-day workshop, and proficiency test. Multiple FISH probe strategies were used to detect 6q-, 11q-, +12, 13q-, 17p-, and IGH rearrangements. Ten specimens were studied by participants who used their own probes (pilot study 1). Of 312 FISH interpretations, 224 (72%) were true-negative, 74 (24%) true-positive, 6 (2%) false-negative, and 8 (3%) false-positive. In pilot study no. 2, each participant studied two specimens using identical FISH probe sets to control for variation due to probe sets and probe strategies. Of 80 FISH interpretations, no false interpretations were identified. At a subsequent workshop, discussions produced agreement on scoring criteria. The proficiency test that followed produced no false-negative results and 4% (3/68) false-positive interpretations. Interpretation disagreements among laboratories were primarily attributable to inadequate normal cutoffs, inconsistent scoring criteria, and the use of different FISH probe strategies. Collaborative organizations that use pooled FISH results may wish to impose more conservative empiric normal cutoff values or use an equivocal range between the normal cutoff and the abnormal reference range to eliminate false-positive interpretations. False-negative results will still occur, and would be expected in low-percentage positive cases; these would likely have less clinical significance than false positive results. Individual laboratories can help by closely following rigorous quality assurance guidelines to ensure accurate and consistent FISH studies in their clinical practice and research.

The TRITON Project: Design and Implementation of an Integrative Translational Research Information Management Platform.

Multi-site consortia have become the preferred setting for team-based translational research programs. Such consortia are able to facilitate increased breadth and depth of basic science and clinical research activities, but also present numerous challenges related to data collection, analysis, storage, and exchange. The Chronic Lymphocytic Leukemia (CLL) Research Consortium (CRC), a s a prototypical instance of such a consortia, uses numerous loosely coupled web applications to address its informatics needs. Over a decade of operations have allowed the CRC to identify usability and computational limitations relative to the preceding information management architecture. In response, the CRC has launched the TRITON project, with the ultimate objective of developing an open-source, extensible, and fully integrative translational research information management platform. In this manuscript, we describe the architecture, design processes, and initial implementation of thatplatform.

Integrating web portlet technologies with caGrid to enable rapid application development: the CRC Patient Study Calendar.

The caGrid middleware provides an extensible platform for the integration of heterogeneous data sources and services; such as those found in geographically distributed research consortia. We describe an architectural approach to the integration of web portlet technologies with caGrid in order to facilitate the rapid development of highly usable presentation models for grid-based data sources and services, using the development of a patient study calendar for the CLL Research Consortium as a motivating use case.

Supporting the design of translational clinical studies through the generation and verification of conceptual knowledge-anchored hypotheses.

The ability to generate hypotheses based upon the contents of large-scale, heterogeneous data sets is critical to the design of translational clinical studies. In previous reports, we have described the application of a conceptual knowledge engineering technique, known as constructive induction (CI) in order to satisfy such needs. However, one of the major limitations of this method is the need to engage multiple subject matter experts to verify potential hypotheses generated using CI. In this manuscript, we describe an alternative verification technique that leverages published biomedical literature abstracts. Our report will be framed in the context of an ongoing project to generate hypotheses related to the contents of a translational research data repository maintained by the CLL Research Consortium. Such hypotheses will are intended to inform the design of prospective clinical studies that can elucidate the relationships that may exist between biomarkers and patient phenotypes.

Relative value of ZAP-70, CD38, and immunoglobulin mutation status in predicting aggressive disease in chronic lymphocytic leukemia.

Leukemia-cell expression of ZAP-70, CD38, or unmutated immunoglobulin heavy chain variable region genes (U-IGHV) each is associated with aggressive disease in patients with chronic lymphocytic leukemia (CLL). To assess the relative strength of each marker, we defined thresholds for designating a case as positive for CD38 or ZAP-70 in a test cohort of 307 patients and used these data-defined criteria to stratify patients in an independent cohort of 705 patients. Multivariable analysis revealed that ZAP-70 was the strongest risk factor. Knowledge of the IGHV mutation status or CD38 did not improve our ability to predict the time to first treatment except for ZAP-70-negative cases, which could be segregated into 2 groups of intermediate-risk or low-risk disease based on whether they expressed unmutated or mutated IGHV. ZAP-70 maintained its high relative prognostic value for the subset of patients with early-stage, asymptomatic disease, including patients evaluated within 1 year of diagnosis. Although it is premature to recommend therapy based on these risk factors, patients with ZAP-70-positive CLL cells should be monitored closely for disease progression as they have a median time from diagnosis to requiring initial therapy by standard criteria of approximately 3 years.

Use of IGHV3-21 in chronic lymphocytic leukemia is associated with high-risk disease and reflects antigen-driven, post-germinal center leukemogenic selection.

We examined the chronic lymphocytic leukemia (CLL) cells of 2457 patients evaluated by the CLL Research Consortium (CRC) and found that 63 (2.6%) expressed immunoglobulin (Ig) encoded by the Ig heavy-chain-variable-region gene (IGHV), IGHV3-21. We identified the amino acid sequence DANGMDV (motif-1) or DPSFYSSSWTLFDY (motif-2) in the Ig heavy-chain (IgH) third complementarity-determining region (HCDR3) of IgH, respectively, used by 25 or 3 cases. The IgH with HCDR3 motif-1 or motif-2, respectively, was paired with Ig light chains (IgL) encoded by IGLV3-21 or IGKV3-20, suggesting that these Ig had been selected for binding to conventional antigen(s). Cases that had HCDR3 motif-1 had a median time from diagnosis to initial therapy comparable with that of cases without a defined HCDR3 motif, as did cases that used mutated IGHV3-21 (n = 27) versus unmutated IGHV3-21 (n = 30). Of 7 examined cases that used Ig encoded by IGHV3-21/IGLV3-21, we found that 5 had a functionally rearranged IGKV allele that apparently had incurred antigendriven somatic mutations and subsequent rearrangement with KDE. This study reveals that CLL cells expressing IGHV3-21/IGLV3-21 most likely were derived from B cells that had experienced somatic mutation and germinal-center maturation in an apparent antigen-driven immune response before undergoing Ig-receptor editing and after germinal-center leukemogenic selection.

Ontology-anchored Approaches to Conceptual Knowledge Discovery in a Multi-dimensional Research Data Repository.

Chronic Lymphocytic Leukemia (CLL) is the most common adult leukemia in the U.S., and is currently incurable. Though a small number of biomarkers that may correlate to risk of disease progression or treatment outcome in CLL have been discovered, few have been validated in prospective studies or adopted in clinical practice. In order to address this gap in knowledge, it is desirable to discover and test hypotheses that are concerned with translational biomarker-to-phenotype correlations. We report upon a study in which commonly available ontologies were utilized to support the discovery of such translational correlations. We have specifically applied a technique known as constructive induction to reason over the contents of a research data repository utilized by the NCI-funded CLL Research Consortium. Our findings indicate that such an approach can produce semantically meaningful results that can inform hypotheses about higher-level relationships between the types of data contained in such a repository.

CRC Tissue Core Management System (TCMS): integration of basic science and clinical data for translational research.

The Chronic Lymphocytic Leukemia (CLL) Research Consortium (CRC) consists of 9 geographically distributed sites conducting a program of research including both basic science and clinical components. The CRC TCMS was designed to capture and integrate basic science and clinical data sets. The system utilizes multiple data modeling methodologies and web-application platforms, and was designed with the high level objectives of providing an extensible, generalizable model for integrating data as required to conduct translational research.

CRC Clinical Trials Management System (CTMS): an integrated information management solution for collaborative clinical research.

The Chronic Lymphocytic Leukemia (CLL) Research Consortium (CRC) consists of 9 geographically distributed sites conducting a program of research including both basic science and clinical components. To enable the CRC's clinical research efforts, a system providing for real-time collaboration was required. CTMS provides such functionality, and demonstrates that the use of novel data modeling, web-application platforms, and management strategies provides for the deployment of an extensible, cost effective solution in such an environment.