Biomedical subjects

Michael LeBlanc

Publications and source records attributed to Michael LeBlanc.

7 recordsLinked to original sources

PubMed2003

Molecular diagnosis of primary mediastinal B cell lymphoma identifies a clinically favorable subgroup of diffuse large B cell lymphoma related to Hodgkin lymphoma.

Using current diagnostic criteria, primary mediastinal B cell lymphoma (PMBL) cannot be distinguished from other types of diffuse large B cell lymphoma (DLBCL) reliably. We used gene expression profiling to develop a more precise molecular diagnosis of PMBL. PMBL patients were considerably younger than other DLBCL patients, and their lymphomas frequently involved other thoracic structures but not extrathoracic sites typical of other DLBCLs. PMBL patients had a relatively favorable clinical outcome, with a 5-yr survival rate of 64% compared with 46% for other DLBCL patients. Gene expression profiling strongly supported a relationship between PMBL and Hodgkin lymphoma: over one third of the genes that were more highly expressed in PMBL than in other DLBCLs were also characteristically expressed in Hodgkin lymphoma cells. PDL2, which encodes a regulator of T cell activation, was the gene that best discriminated PMBL from other DLBCLs and was also highly expressed in Hodgkin lymphoma cells. The genomic loci for PDL2 and several neighboring genes were amplified in over half of the PMBLs and in Hodgkin lymphoma cell lines. The molecular diagnosis of PMBL should significantly aid in the development of therapies tailored to this clinically and pathogenetically distinctive subgroup of DLBCL.

Adult↗

PubMed2003

A phase 2 trial of CHOP chemotherapy followed by tositumomab/iodine I 131 tositumomab for previously untreated follicular non-Hodgkin lymphoma: Southwest Oncology Group Protocol S9911.

Advanced follicular lymphoma is incurable with conventional chemotherapy and radiotherapy. The Southwest Oncology Group (SWOG) conducted a phase 2 trial (S9911) of a novel regimen consisting of 6 cycles of CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisone) chemotherapy followed 4 to 8 weeks later by tositumomab/iodine I 131 tositumomab (anti-CD20 antibody) in 90 eligible patients with previously untreated, advanced stage follicular lymphoma. Treatment was well tolerated. Reversible myelosuppression was the main adverse event and was more severe during CHOP chemotherapy than following radioimmunotherapy. The overall response rate to the entire treatment regimen was 90%, including 67% complete remissions (CRs plus unconfirmed CRs [CRu's]) and 23% partial remissions (PRs). Twenty-seven (57%) of the 47 fully evaluable patients who achieved less than a CR with CHOP improved their remission status after tositumomab/iodine I 131 tositumomab. With a median follow-up of 2.3 years, the 2-year progression-free survival (PFS) was estimated to be 81%, with a 2-year overall survival of 97%. This study has established the feasibility, tolerability, and efficacy of this regimen for patients with advanced follicular lymphoma. This novel treatment appears promising compared with the SWOG's historical experience using CHOP alone and is currently being compared with CHOP plus rituximab in a randomized phase 3 trial (S0016).

Adult↗

PubMed2003

Directed indices for exploring gene expression data.

MOTIVATION: Large expression studies with clinical outcome data are becoming available for analysis. An important goal is to identify genes or clusters of genes where expression is related to patient outcome. While clustering methods are useful data exploration tools, they do not directly allow one to relate the expression data to clinical outcome. Alternatively, methods which rank genes based on their univariate significance do not incorporate gene function or relationships to genes that have been previously identified. In addition, after sifting through potentially thousands of genes, summary estimates (e.g. regression coefficients or error rates) algorithms should address the potentially large bias introduced by gene selection. RESULTS: We developed a gene index technique that generalizes methods that rank genes by their univariate associations to patient outcome. Genes are ordered based on simultaneously linking their expression both to patient outcome and to a specific gene of interest. The technique can also be used to suggest profiles of gene expression related to patient outcome. A cross-validation method is shown to be important for reducing bias due to adaptive gene selection. The methods are illustrated on a recently collected gene expression data set based on 160 patients with diffuse large cell lymphoma (DLCL).

Algorithms↗

PubMed2003

The value of augmented preparative regimens combined with an autologous bone marrow transplant for the management of relapsed or refractory Hodgkin disease: a Southwest Oncology Group phase II trial.

Several single-institution pilot studies have suggested that augmented preparative regimens, including those containing total body irradiation combined with an autologous bone marrow transplantation, are superior to standard regimens for the treatment of relapsed or refractory Hodgkin disease. On the basis of these data, we undertook, in the cooperative group setting, a phase II trial of augmented preparative regimens for patients experiencing treatment failure with conventional chemotherapy. Eighty-one patients with either sensitive or refractory (induction failures or chemoresistant) relapse received etoposide (60 mg/kg), cyclophosphamide (100 mg/kg), and either total body irradiation (12 Gy) or, if previously irradiated, carmustine (15 mg/kg), followed by an autologous bone marrow transplantation. Progression-free (PFS) and overall (OS) survival were estimated, and a Cox regression model was used to assess potential prognostic variables. The 5-year PFS and OS for the 74 eligible patients treated at 20 Southwest Oncology Group centers were 41% (95% confidence interval [CI], 29%-53%) and 54% (95% CI, 43%-65%), respectively, despite a median remission after initial chemotherapy of only 6 months. The 3-year OS for those whose induction therapy failed was 72% (95% CI, 52%-93%). There was 1 (1.4%) early treatment-related death, 2 late deaths due to lung toxicity, and only 1 death due to myelodysplasia. There were no differences in PFS or OS on the basis of regimen or chemosensitivity. A Cox prognostic factor analysis determined that >2 prior regimens, relapse in a radiated field, and extranodal disease were adverse prognostic factors. Among the 46 patients who received prior radiotherapy, the 5-year OS was 38% (95% CI, 14%-61%) for patients with 2 or 3 adverse factors, versus 60% (95% CI, 42%-78%) for those with 0 factors or 1 adverse factor. Augmented preparative regimens seem promising for the treatment of relapsed or refractory Hodgkin disease, without an increase in regimen-related mortality. A poor-prognosis group was identified that should be treated with novel therapies.

Adolescent↗

PubMed2003

The proliferation gene expression signature is a quantitative integrator of oncogenic events that predicts survival in mantle cell lymphoma.

We used gene expression profiling to establish a molecular diagnosis of mantle cell lymphoma (MCL), to elucidate its pathogenesis, and to predict the length of survival of these patients. An MCL gene expression signature defined a large subset of MCLs that expressed cyclin D1 and a novel subset that lacked cyclin D1 expression. A precise measurement of tumor cell proliferation, provided by the expression of proliferation signature genes, identified patient subsets that differed by more than 5 years in median survival. Differences in cyclin D1 mRNA abundance synergized with INK4a/ARF locus deletions to dictate tumor proliferation rate and survival. We propose a quantitative model of the aberrant cell cycle regulation in MCL that provides a rationale for the design of cell cycle inhibitor therapy in this malignancy.

ADP-Ribosylation Factors↗

PubMed2002

Evaluating test statistics to select interesting genes in microarray experiments.

A randomization procedure to evaluate the significance level and the false-discovery rate in complex microarray experiments is proposed. A related graph can be used to compare different test statistics that can be used to analyze the same experiment. This graph is closely related to receiver operator characteristic (ROC) curves. The proposed method is applied to a subset of the data from a cell-line experiment related to Huntington's disease. A small simulation study compares the effectiveness of the proposed procedure with the significance analysis of microarrays (SAM) procedure.

Computer Simulation↗

PubMed2002

Partitioning and peeling for constructing prognostic groups.

We investigate methods for identifying groups of patients with different prognosis. Our focus is on procedures that yield interpretable descriptions for groups of patients and corresponding regions of the predictor space. These strategies include tree-based methods and techniques which construct a single prognostic group through 'peeling' or refining of a larger group patients. The peeling methods are relatively new and are developed in detail. Simulations and examples for describing groups of patients with poor outcomes using data from a clinical trial for patients with multiple myeloma are presented.

Algorithms↗