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Wing C Chan

Publications and source records attributed to Wing C Chan.

51 records · Page 3Linked 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

Oligonucleotide microarrays demonstrate the highest frequency of ATM mutations in the mantle cell subtype of lymphoma.

Mutations have been described in the ataxia telangiectasia mutated (ATM) gene in small numbers of cases of lymphoid neoplasia. However, surveys of the ATM mutation status in lymphoma have been limited due to the large size (62 exons) and complex mutational spectrum of this gene. We have used microarray-based assays with 250,000 oligonucleotides to screen lymphomas from 120 patients for all possible ATM coding and splice junction mutations. The subtypes included were diffuse large B cell, mantle cell, immunoblastic large B cell, follicular, posttransplant lymphoproliferative disorder, and peripheral T cell lymphoma. We found the highest percentage of ATM mutations within the mantle cell (MCL) subtype (43%, 12 of 28 cases), followed by a lower level (10% of cases) in the other subtypes. A frame-shift ATM mutation was found in one peripheral T cell lymphoma patient. In six MCL cases examined, four ATM variants were due to somatic mutation in the tumor cells whereas two others seemed to be germ-line in origin. There was no difference in p53 mutation status in the ATM mutant and wild-type groups of MCL. There was no statistically significant difference in the median overall survival of patients with wild-type vs. mutated ATM in MCL. Additional mutational and functional analyses are needed to determine whether ATM mutations contribute to the development and progression of MCL or are just the consequence of genomic instability in MCL.

Ataxia Telangiectasia Mutated Proteins↗
PubMed2003

Two newly characterized germinal center B-cell-associated genes, GCET1 and GCET2, have differential expression in normal and neoplastic B cells.

A group of genes are highly expressed in normal germinal center (GC) B cells and GC B-cell-derived malignancies based on cDNA microarray analysis. Two new genes, GCET1 (germinal center B-cell expressed transcript 1) and GCET2, were cloned from selected expressed sequence tags (IMAGE clone 1334260 and 814622, respectively). GCET1 is located on chromosome 14q32 and has four splicing isoforms, of which the longest one is 1787 bp and encodes a 435-amino acid protein. GCET2 is located on 3q13.13, and the cloned fragment is 3270 bp, which encodes a protein of 178 amino acids. Blast search showed that GCET1 has a highly conserved serine proteinase inhibitor (SERPIN) domain and is located on a chromosomal locus containing seven other SERPIN family members. GCET2 is a likely homologue of the mouse gene M17, a GC-expressed transcript. Analysis of the GCET2 protein sequence indicated that it may be involved in signal transduction in the cytoplasm. Northern blot and real-time polymerase chain reaction analyses confirmed that GCET1 is highly restricted to normal GC B cells and GCB-cell-derived cell lines. Although GCET2 is also a useful marker for normal and neoplastic GC B cells, it has a wider range of expression including immature B and T cells. Real-time polymerase chain reaction assay showed that both GCET1 and GCET2 are preferentially expressed in follicular lymphoma and diffuse large B-cell lymphoma with GC B-cell differentiation, confirming previous microarray gene expression analysis, but neither one is entirely specific. Multiple markers are necessary to differentiate the GCB from the activated B-cell type of diffuse large B-cell lymphoma with a high degree of accuracy.

Amino Acid Sequence↗
PubMed2003

The distribution of gene segments in T-cell receptor gamma gene rearrangements demonstrates the need for multiple primer sets.

Limited data exist regarding the distribution of gene segments used in T-cell receptor gamma gene rearrangements (TCR gamma GR) in T-cell lymphoproliferative disorders. The reported efficacy of TCR gamma GR protocols ranges from 60% to greater than 90%. Laboratories reporting a lower detection rate tend to use a limited set of primers. The goal of our study was to provide TCR gamma GR data to demonstrate the molecular biological basis for needing multiple primer sets targeting all gene segments. Sixty cases with a confirmed histological diagnosis of a T-cell lymphoproliferative disorder and TCR gamma GR were identified in our lymphoma registry from 1995 to 2001. DNA was obtained from fresh/frozen tissue, cell lysates, or paraffin-embedded tissue. Variable (V gamma) region gene segments were identified using denaturing gradient gel electrophoresis, which was used to select the cases in the study. Capillary electrophoresis using fluorescent-labeled joining (J gamma) region primers was performed to identify J gamma segments. Sixty cases contained a total of 98 TCR gamma GR, as some cases have more than one rearrangement. The most frequent gene segment combination involved the V gamma 1-8 and J gamma 1/2 segments. If a single primer set directed at these two segments were used for clinical diagnosis, that pair of primers would only diagnose 67% of cases as positive for TCR gamma GR. Our gene segment distribution data emphasize the importance of using a comprehensive set of V gamma and J gamma primers for an optimal detection rate of TCR gamma GR. Protocols with limited numbers of primers should be reconsidered.

DNA↗
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↗
PubMed2003

Diffuse large B-cell lymphoma arising in nodular lymphocyte predominant hodgkin lymphoma. A report of 21 cases from the Nebraska Lymphoma Study Group.

We sought to investigate the clinical characteristics and pathologic features and survival outcome of patients with diffuse large B-cell lymphoma (DLBCL) arising in nodular lymphocyte predominant Hodgkin's disease (NLPHL), since controversy regarding their prognosis exists in the literature. Twenty-one patients with DLBCL arising either concurrently with (n = 7) or subsequent to (n = 14) a diagnosis of NLPHL were identified in the Nebraska Lymphoma Study Group Registry. The clinical and pathologic features of the cases were evaluated, and survival analysis was performed from the time of diagnosis of DLBCL. The median time to the development of DLBCL in those with prior NLPHL was only one year (range, 0.5-24 years). The median age of the patients at the time of diagnosis of DLBCL was 46 years (range, 18-72 years) and the male to female ratio was 17:4. Ten patients presented with nodal DLBCL only, six patients presented with both nodal and extranodal involvement, and five patients presented with only extranodal DLBCL. Eleven patients had limited stage (I/II) disease and 10 had advanced stage (III/IV) disease. The median overall survival (OS) and failure-free survival (FFS) of the entire group was 35 months and 11 months, respectively, and the predicted five-year OS and FFS was 31 and 18%, respectively. There were no significant differences in the survival outcomes between patients with DLBCL arising in NLPHL and age- and sex- matched patients with de novo DLBCL. In conclusion, our findings suggest that patients with DLBCL arising in NLPHL have a prognosis similar to those with de novo DLBCL and should be treated aggressively.

Adolescent↗
PubMed2002

A significant diffuse component predicts for inferior survival in grade 3 follicular lymphoma, but cytologic subtypes do not predict survival.

Grade 3 follicular lymphoma (FL3) is thought to have an aggressive clinical course. On the basis of possible biologic differences, the new World Health Organization (WHO) classification of lymphoma suggests further subdivision of FL3 into grades 3a and 3b and states that the percentage of involvement by diffuse large B-cell lymphoma (DLBCL) should also be reported. However, the clinical implications of these features are unclear. Therefore, we studied 190 newly diagnosed patients with lymph node-based FL3 who received anthracycline-containing combination chemotherapy. The follicular component was subclassified as grade 3a (FL3a) or grade 3b (FL3b) according to the WHO criteria, or as follicular large cleaved cell type (FLC). The percentage of a diffuse component, if present, was also recorded. Of the 190 cases, there were 107 FL3a (56%), 53 FL3b (28%), and 30 FLC (16%) cases. Diffuse areas were seen in 72 cases (31 FL3a, 28 FL3b, and 13 FLC). There were no significant differences in the clinical characteristics, overall survival, or event-free survival between patients with grades FL3a, FL3b, or FLC. However, those cases with a predominant diffuse component (> 50% diffuse) had a significantly worse overall survival (P =.0037) and event-free survival (P =.012). Therefore, we conclude that the subdivision of FL3 into cytologic subtypes does not appear to be important clinically. However, patients with FL3 having a diffuse component of more than 50% have an inferior survival that is similar to the survival of those with DLBCL.

Adolescent↗
PubMed2002

The use of molecular profiling to predict survival after chemotherapy for diffuse large-B-cell lymphoma.

BACKGROUND: The survival of patients with diffuse large-B-cell lymphoma after chemotherapy is influenced by molecular features of the tumors. We used the gene-expression profiles of these lymphomas to develop a molecular predictor of survival. METHODS: Biopsy samples of diffuse large-B-cell lymphoma from 240 patients were examined for gene expression with the use of DNA microarrays and analyzed for genomic abnormalities. Subgroups with distinctive gene-expression profiles were defined on the basis of hierarchical clustering. A molecular predictor of risk was constructed with the use of genes with expression patterns that were associated with survival in a preliminary group of 160 patients and was then tested in a validation group of 80 patients. The accuracy of this predictor was compared with that of the international prognostic index. RESULTS: Three gene-expression subgroups--germinal-center B-cell-like, activated B-cell-like, and type 3 diffuse large-B-cell lymphoma--were identified. Two common oncogenic events in diffuse large-B-cell lymphoma, bcl-2 translocation and c-rel amplification, were detected only in the germinal-center B-cell-like subgroup. Patients in this subgroup had the highest five-year survival rate. To identify other molecular determinants of outcome, we searched for individual genes with expression patterns that correlated with survival in the preliminary group of patients. Most of these genes fell within four gene-expression signatures characteristic of germinal-center B cells, proliferating cells, reactive stromal and immune cells in the lymph node, or major-histocompatibility-complex class II complex. We used 17 genes to construct a predictor of overall survival after chemotherapy. This gene-based predictor and the international prognostic index were independent prognostic indicators. CONCLUSIONS: DNA microarrays can be used to formulate a molecular predictor of survival after chemotherapy for diffuse large-B-cell lymphoma.

Antibiotics, Antineoplastic↗
PubMed2002

Autologous transplantation for aggressive non-Hodgkin's lymphoma: results of a randomized trial evaluating graft source and minimal residual disease.

PURPOSE: To determine whether the source of autologous hematopoietic stem cells altered the clinical outcomes of patients undergoing high-dose chemotherapy and hematopoietic stem-cell transplantation (HSCT) for aggressive non-Hodgkin's lymphoma (NHL). PATIENTS AND METHODS: Of 105 high-risk, persistent, or relapsed NHL patients slated for an autologous HSCT entered onto this trial, 93 eligible patients were randomized to receive cytokine-naive autologous bone marrow transplantation (ABMT) (n = 46) or mobilized peripheral-blood stem-cell transplantation (PBSCT) (n = 47). All patients received carmustine, etoposide, cytarabine, and cyclophosphamide as the conditioning regimen. PBSCT patients also received identical mobilization with granulocyte colony-stimulating factor (G-CSF) 10 microg/kg/d, and both groups received G-CSF 5 microg/kg/d after the infusion of the stem-cell product until neutrophil engraftment. RESULTS: PBSCT patients had significantly faster engraftment of all cell lineages: median time to absolute neutrophil count > or = 500/microL, 10 days versus 13 days on the ABMT arm; median time to platelet count greater than 20,000/microL untransfused, 11 days versus 15 days on the ABMT arm; and median time to RBC transfusion independence, 8 days versus 16 days on the ABMT arm. The complete response rate was 72% for PBSCT and 54% for ABMT. The death rate before posttransplant day 100 was 2% on the ABMT arm and 6% on PBSCT arm. Event-free survival was 37% for PBSCT and 37% for ABMT. However, overall survival for PBSCT was 61% compared with 43% for ABMT. CONCLUSION: Patients with aggressive NHL receiving HSCT randomized to PBSCT demonstrated improved neutrophil engraftment and platelet and RBC transfusion independence. The complete response rate and EFS were not statistically different by randomization arm. Patients whose harvests were positive for minimal residual disease by molecular analysis had poorer EFS.

Adult↗
PubMed2002

The t(14;18) defines a unique subset of diffuse large B-cell lymphoma with a germinal center B-cell gene expression profile.

Recently we have identified subgroups of de novo primary diffuse large B-cell lymphoma (DLBCL) based on complementary DNA microarray-generated gene expression profiles. To correlate the gene expression profiles with cytogenetic abnormalities in these DLBCLs, we examined the occurrence of the t(14;18)(q32;q21) in the 2 distinctive subgroups of DLBCL: one with the germinal center B-cell gene expression signature and the other with the activated B cell-like gene expression signature. The t(14;18) was detected in 7 of 35 cases (20%). All 7 t(14;18)-positive cases had a germinal center B-cell gene expression profile, representing 35% of the cases in this subgroup, and 6 of these 7 cases had very similar gene expression profiles. The expression of bcl-2 and bcl-6 proteins was not significantly different between the t(14;18)-positive and -negative cases, whereas CD10 was detected only in the group with the germinal center B-cell expression profile, and CD10 was most frequently expressed in the t(14;18)-positive cases. This study supports the validity of subdividing DLBCL into 2 major subgroups by gene expression profiling, with the t(14;18) being an important event in the pathogenesis of a subset of DLBCL arising from germinal center B cells. CD10 protein expression is useful in identifying cases of DLBCL with a germinal center B-cell gene expression profile and is often expressed in cases with the t(14;18).

Chromosome Mapping↗
PubMed2002

Hodgkin's disease in the elderly: improved treatment outcome with a doxorubicin-containing regimen.

PURPOSE: Hodgkin's disease (HD) is a malignancy that displays a bimodal age distribution. Previous reports of treatment in patients greater-than-or-equal 60 years have found a poor outcome, particularly in patients with advanced disease. Because of an improved side-effect profile, the regimen of chlorambucil, vinblastine, procarbazine, and prednisone (ChlVPP) has been proposed for use in elderly patients. PATIENTS AND METHODS: From September 1982 to May 1998, 262 patients with previously untreated HD received either ChlVPP (n = 176) or ChlVPP plus doxorubicin/bleomycin/vincristine (ChlVPP/ABV hybrid; n = 86). Fifty-six patients were greater-than-or-equal 60 years old, and 206 were younger than 60 years. RESULTS: The 5-year overall survival (OS; 87% v 39%) and the 5-year event-free survival (EFS; 75% v 31%) favored patients younger than 60 years of age. Prognostic factors analyzed in patients greater-than-or-equal 60 years of age, other than type of therapy, included sex, stage, Karnofsky performance score, lactic dehydrogenase, number of extranodal sites, B symptoms, size of largest mass, and histologic subtype. In patients older than 60 years, none of the clinical features was a statistically significant predictor of EFS; however, ChlVPP/ABV hybrid was associated with a decreased risk of an event (relative risk, 0.40; 95% confidence interval, 0.19 to 0.83; P =.014) compared with ChlVPP. The 5-year OS for patients greater-than-or-equal 60 years who received ChlVPP was 30%, compared with 67% for those patients receiving the ChlVPP/ABV regimen (P =.0086) CONCLUSION: Patients greater-than-or-equal 60 years with HD who require chemotherapy are better treated with ChlVPP/ABV hybrid than with ChlVPP alone.

Age Factors↗
PubMed2002

Cytogenetic characterization of diffuse large cell lymphoma using multi-color fluorescence in situ hybridization.

We have employed multi-color fluorescence in situ hybridization (M-FISH) to characterize the cytogenetic changes in 20 diffuse large B-cell lymphomas (DLBCL), that contained complex and partially characterized karyotypes. The M-FISH analysis helped to delineate 94% of the unidentified abnormalities and assisted in redefining some unidentified/misidentified karyotypic changes. Recurrent breakpoints observed in approximately 20% cases included 14q32, 3p21, 3q27, 22q12, 1q25, and 18q21 (in decreasing order), and 1p22, 1q21, 4q31, 6q21, and 8q24 (in four cases each). Numerical gain of chromosomes 7, 9, 12, and X and loss of chromosomes 1, 4, 6, 17, and Y, were noted in approximately 20% of cases. The minimum deleted regions encompassed 6q21-q25, 1p22-p36, 1q32-q44, 2p23-p25, 4q31-q35, 13p13-q14, and 17p11-p13. Two cases presented with a sole structural abnormality, and one contained a der(17)t(9;17)(p21;p13), which has not been reported earlier as a sole abnormality in DLBCL. Upon completely characterizing the karyotypes, we observed with interesting that in 55% of the cases, more than one BCL gene bearing regions was involved in translocations. In the remaining 45%, where only one or none of the BCL gene regions was involved in a rearrangement, we observed the loss of chromosomes 6 and/or 17 or partial deletions of 6q and/or 17p or gain of 7 and/or 12. Our findings suggest that, although BCL2 and BCL6 are most often implicated in DLBCL, the possibility of the disruptions of BCL3, BCL8, BCL9, and BCL10 as a "primary event" in DLBCL cannot be ruled out. Most often, a combination of events may be necessary for the genesis of DLBCL or progression of follicular lymphoma to DLBCL. Overall, M-FISH has enhanced our ability to provide a comprehensive karyotypic analysis, and has helped in defining the importance of BCL3, BCL8, BCL9, and BCL10 carrying breakpoints in DLBCL.

Chromosome Aberrations↗
PubMed2002

The t(14;18) and bcl-2 expression are present in a subset of primary cutaneous follicular lymphoma: association with lower grade.

According to the European Organization for Research and Treatment of Cancer classification, primary cutaneous follicle center cell lymphoma is not associated with the t(14;18)(q32;q21) and only rarely expresses bcl-2 protein. To further investigate this issue, we evaluated a series of 20 patients (14 men, 6 women) with primary cutaneous follicular lymphoma (PCFL). The presenting skin lesion was located in the head and neck region in 16 of 20 patients. Most cases were grade 2 (6/20) or grade 3 (13/20), and all had a follicular architecture. Immunohistochemical analysis demonstrated bcl-2 expression in 8 cases (40%), and expression was inversely related to the grade. Of 7 grade 1 or 2 cases, 5 (71%) were positive, whereas only 3 (23%) of 13 grade 3 cases were positive for bcl-2. Clonal immunoglobulin heavy chain gene rearrangements were detected in 9 (45%) of 20 cases. In 4 (20%) of 20 cases, we identified the major breakpoint of the t(14;18) by polymerase chain reaction, 3 of which were grade 1 or 2. We conclude that bcl-2 protein expression and the t(14;18) are present in a subset of PCFL, particularly in lower grade cases.

Adult↗
PubMedDate not supplied

Unsual ocular metastasis from breast cancer.

Herein a clinical case of an unusual metastasis from breast cancer to the retina and vitreous confirmed by diagnostic vitrectomy is described. Further investigation also demonstrated the central nervous system metastasis.

Adenocarcinoma↗