Biomedical subjects

Yasodha Natkunam

Publications and source records attributed to Yasodha Natkunam.

At least 19 recordsLinked to original sources

PubMed2006

The oncoprotein LMO2 is expressed in normal germinal-center B cells and in human B-cell lymphomas.

We previously developed a multivariate model based on the RNA expression of 6 genes (LMO2, BCL6, FN1, CCND2, SCYA3, and BCL2) that predicts survival in diffuse large B-cell lymphoma (DLBCL) patients. Since LMO2 emerged as the strongest predictor of superior outcome, we generated a monoclonal anti-LMO2 antibody in order to study its tissue expression pattern. Immunohistologic analysis of over 1200 normal and neoplastic tissue and cell lines showed that LMO2 protein is expressed as a nuclear marker in normal germinal-center (GC) B cells and GC-derived B-cell lines and in a subset of GC-derived B-cell lymphomas. LMO2 was also expressed in erythroid and myeloid precursors and in megakaryocytes and also in lymphoblastic and acute myeloid leukemias. It was rarely expressed in mature T, natural killer (NK), and plasma cell neoplasms and was absent from nonhematolymphoid tissues except for endothelial cells. Hierarchical cluster analysis of immunohistologic data in DLBCL demonstrated that the expression profile of the LMO2 protein was similar to that of other GC-associated proteins (HGAL, BCL6, and CD10) but different from that of non-GC proteins (MUM1/IRF4 and BCL2). Our results warrant inclusion of LMO2 in multivariate analyses to construct a clinically applicable immunohistologic algorithm for predicting survival in patients with DLBCL.

Adaptor Proteins, Signal Transducing↗

PubMed2006

Expression of the human germinal center-associated lymphoma (HGAL) protein identifies a subset of classic Hodgkin lymphoma of germinal center derivation and improved survival.

The human germinal-center-associated lymphoma (HGAL) gene and its cognate protein are expressed in a germinal center (GC)-specific manner. Its expression in classic Hodgkin lymphoma (cHL) prompted us to address whether HGAL expression could distinguish biologically distinct subgroups of cHL. Tissue microarrays from 145 patients treated with curative intent showed HGAL staining in 75% and was closely correlated with MUM1/IRF4 (92%) expression. BCL6 (26%), CD10 (0%), BCL2 (31%), Blimp1 (0.02%), and Epstein-Barr virus (EBV) (20%) showed no specific correlation; neither did phospho-STAT6, a key mediator of IL-4 and IL-13 signaling that induces HGAL and is implicated in cHL pathogenesis. In our study cohort, the 5-year overall survival (OS) correlated with young age (less than 45 years, P < .001), low stage (stage I and II, P = .04), and low International Prognostic Score (P = .002). In univariate analysis, HGAL expression was associated with improved OS (P = .01) and failure-free survival (FFS) (P = .05) but was not independent of other factors in multivariate analysis of OS or FFS. The expression of the GC-specific marker HGAL in a subset of cHL suggests that these cHLs retain characteristics of GC-derived lymphomas. The association with improved OS in univariate but not multivariate analysis suggests that HGAL expression is related to known clinical parameters of improved survival.

Adult↗

PubMed2006

EBV can protect latently infected B cell lymphomas from death receptor-induced apoptosis.

The relationship between EBV infection and sensitivity to death receptor (DR)-induced apoptosis is poorly understood. Using EBV- and EBV+ BJAB cells, we provide the first evidence that EBV can protect latently infected B cell lymphomas from apoptosis triggered through Fas or TRAIL receptors. Caspase 8 activation was impaired and cellular FLIP recruitment was enriched in death-inducing signaling complexes formed in EBV-infected BJAB cells relative to parent BJAB cells. Furthermore, latent membrane protein 1 expression alone could reduce caspase activation and confer partial resistance to DR apoptosis in BJAB cells. This protective effect was dependent on C-terminal activating region 2-driven NF-kappaB activation, which in turn up-regulated cellular FLIP expression in latent membrane protein 1+ BJAB cells. Thus, the ability of latent EBV to block DR apoptosis may help to ensure the survival of host cells during B cell differentiation, and contribute to the development of B cell lymphomas, especially in immunocompromised individuals.

Apoptosis↗

PubMed2006

Prognostic immunohistologic markers in human tumors: why are so few used in clinical practice?

Technological advances in gene cloning and genome-wide analyses have greatly increased the number of new tumor markers that can be detected by immunohistologic techniques. While many of these have been evaluated with respect to prognosis, there is a striking discrepancy between the number of markers reported to confer prognostic information and those that are used in clinical practice. We argue that lessons learned from epidemiological studies are applicable to studies of immunohistologic markers; in particular, advances in both fields can be vitiated by non-causal associations. We suggest that the most valuable immunohistologic markers are those that reflect genetic abnormalities, that are linked to the cell of origin, or that reflect tumor infiltrating cells or stromal reactions. It should also be appreciated that a marker that is genuinely predictive of prognosis may nevertheless not find any application in clinical practice if it becomes obsolete through the introduction of newer therapies or because there is no choice of alternative treatment strategies.

Biomarkers, Tumor↗

PubMed2006

CD10 expression in peripheral T-cell lymphomas complicated by a proliferation of large B-cells.

CD10 expression by the neoplastic T cells in angioimmunoblastic T-cell lymphoma was recently described. As cases of peripheral T-cell lymphoma, unspecified, fail to show similar CD10 expression, this feature helps discriminate between these two entities, particularly in cases exhibiting morphologic overlap. Given these findings, we studied CD10 expression in a subtype of peripheral T-cell lymphoma known as peripheral T-cell lymphoma complicated by a proliferation of large B cells and compared it with angioimmunoblastic T-cell lymphoma and angioimmunoblastic T-cell lymphoma with a large B-cell proliferation. A total of 33 cases were identified including peripheral T-cell lymphoma complicated by a proliferation of large B cells (10), angioimmunoblastic T-cell lymphoma (10) and angioimmunoblastic T-cell lymphoma with a large B-cell proliferation (13). Diagnoses were established by hematoxylin and eosin (H&E) stain, immunohistochemistry and/or molecular findings (polymerase chain reaction for T-cell receptor-gamma gene rearrangement). Two of 10 cases of peripheral T-cell lymphoma complicated by a proliferation of large B cells showed aberrant CD10 expression (20%) compared to 9/10 cases of angioimmunoblastic T-cell lymphoma (90%) and 8/13 of angioimmunoblastic T-cell lymphoma with a large B-cell proliferation (62%). One case each of angioimmunoblastic T-cell lymphoma and angioimmunoblastic T-cell lymphoma with a large B-cell proliferation showed a rare, but not unequivocal, CD10+ atypical cell. Four cases of angioimmunoblastic T-cell lymphoma with a large B-cell proliferation were CD10 negative. Of the 2 CD10+ peripheral T-cell lymphoma complicated by a proliferation of large B cells, one had no H&E or IHC features of angioimmunoblastic T-cell lymphoma and showed only a rare positive cell. The second case, a lung biopsy, exhibited diffuse CD10 tumor cell positivity. The predominant staining pattern in the CD10+ cases was characterized by scattered, mostly individual, morphologically neoplastic cells. A rare case showed clusters of positive cells. Our data indicate that only 20% of cases of peripheral T-cell lymphoma complicated by a proliferation of large B cells show CD10 expression by the neoplastic T cells in contrast to angioimmunoblastic T-cell lymphoma and angioimmunoblastic T-cell lymphoma with a large B-cell proliferation which exhibit CD10 staining in 90 and 62% of cases, respectively. This finding does not reach statistical significance with a P-value of 0.57 (Fisher's exact test). As these entities appear to be biologically distinct and may portend different overall survivals, CD10 expression may serve as an additional discriminating criterion.

Adult↗

PubMed2006

Low CD27 expression in plasma cell dyscrasias correlates with high-risk disease: an immunohistochemical analysis.

Genome-wide expression studies using complementary DNA microarrays recently suggested a number of intriguing candidate genes for distinguishing plasma cell dyscrasias. Our objective was to test select markers using immunohistochemical analysis and a tissue microarray from paraffin-embedded bone marrow core biopsy specimens obtained from 8 patients with monoclonal gammopathy of undetermined significance, 17 with plasmacytoma, 160 with multiple myeloma, and 15 with plasma cell leukemia (PCL). We immunostained serial sections for CD138, CD27, CD56, p27, Ki-67, CD3, and CD20. Each core was scored in duplicate by observers blinded to phenotype and reported as the average percentage of CD138+ cells. The Mann-Whitney U test was used to determine significance between groups. PCL showed significantly less immunostaining for CD27 (P < .01) and p27 (P < .05) compared with plasmacytoma and multiple myeloma. Low CD27 expression also was associated with plasmacytoma progression to multiple myeloma (P <.05). Our results support the hypothesis that low CD27 expression correlates with high-risk disease, including primary PCL and decreased progression-free survival in solitary plasmacytoma.

Biomarkers, Tumor↗

PubMed2006

The differential expression of LCK and BAFF-receptor and their role in apoptosis in human lymphomas.

BACKGROUND AND OBJECTIVES: We explored the expression of LCK and BAFF-R (B-cell activating factor receptor) both of which are known to play a role in signaling and apoptosis, in routine tissue biopsies. It was hypothesized that their expression patterns might yield information on apoptosis as it occurs in normal and reactive lymphoid cells, and also be of value for the detection of lymphoma subtypes. DESIGN AND METHODS: Both molecules were studied in paraffin-embedded tissue sections and cell lines by immunoperoxidase staining, and were also studied by western blotting. Human tonsillar B-cell subsets were analyzed by flow cytometry for LCK expression. RESULTS: LCK was detected for the first time in germinal centers and, at lower levels, in mantle zone B cells. The presence of LCK in B cells was confirmed by western blotting. Cross-linking surface IgM reduced LCK expression whereas cross-linking surface CD40 appeared to have the opposite effect. BAFF-R was present on mantle zone B cells but absent or weakly expressed in germinal center cells. Most lymphomas of germinal center origin (e.g. follicular lymphoma) and also many mantle cell lymphomas, chronic lymphocytic leukemia (CLL) and most T-cell neoplasms expressed LCK. In contrast, BAFF-R was expressed in a variety of B-cell lymphomas, but often absent in grade 3 follicular lymphomas and diffuse large B-cell lymphomas (DLBCL). Both LCK-positive and BAFF-R-positive DLBCL tended to be of germinal-center phenotype. INTERPRETATION AND CONCLUSIONS: The reciprocal expression pattern of LCK and BAFF-R in germinal center and mantle zone B cells may reflect their opposing roles in apoptosis. Their detection in lymphoma tissue biopsies may therefore be of clinical relevance in predicting response to treatment.

Apoptosis↗

PubMed2005

Cytologic diagnosis of Burkitt lymphoma.

BACKGROUND: The diagnosis and classification of lymphoma require correlation of morphologic, immunophenotypic, and molecular-cytogenetic studies. Fine-needle aspiration biopsy (FNAB) is a valuable diagnostic technique that allows material to be collected for these ancillary studies, and for morphologic evaluation. METHODS: The authors report a series of seven cases clinically or morphologically suspicious for Burkitt lymphoma. Fluorescence in situ hybridization studies (FISH) for c-myc were performed on FNAB material and correlated with cytologic and immunophenotypic data. RESULTS: Six of seven specimens were positive for c-myc rearrangement by FISH. However, only three of these cases represented Burkitt lymphoma, with one additional case of atypical Burkitt lymphoma. The other cases included diffuse large B-cell lymphoma, monomorphic posttransplant B-cell lymphoma, and an aggressive B-cell lymphoma, with the latter case negative for c-myc rearrangement by FISH. Of 2 non-Burkitt lymphoma specimens tested, 1 was positive for the immunoglobulin H/bcl-2 rearrangement, in addition to the c-myc rearrangement, suggesting transformation from a lower grade lymphoma. CONCLUSIONS: These cases illustrated the value of FNAB in the diagnosis of Burkitt lymphoma, as well as the importance of obtaining material for, and integrating results of, ancillary studies for the final diagnosis.

Adult↗

PubMed2005

Transmembrane adaptor molecules: a new category of lymphoid-cell markers.

Transmembrane adaptor proteins (of which 7 have been identified so far) are involved in receptor signaling in immune cells. They have only a short extracellular region, with most of the molecule comprising a substantial intracytoplasmic region carrying multiple tyrosine residues that can be phosphorylated by Src- or Syk-family kinases. In this paper, we report an immunohistologic study of 6 of these molecules in normal and neoplastic human tissue sections and show that they are restricted to subpopulations of lymphoid cells, being present in either T cells (LAT, LIME, and TRIM), B cells (NTAL), or subsets of both cell types (PAG and SIT). Their expression in neoplastic lymphoid cells broadly reflects that of normal lymphoid tissue, including the positivity of plasma cells and myeloma/plasmacytoma for LIME, NTAL, PAG, and SIT. However, this study also revealed some reactions that may be of diagnostic/prognostic value. For example, lymphocytic lymphoma and mantle-cell lymphoma showed similar profiles but differed clearly from follicle-center lymphoma, whereas PAG tended to be selectively expressed in germinal center-derived subsets of diffuse large B-cell lymphoma. These molecules represent a potentially important addition to the panel of immunophenotypic markers detectable in routine biopsies that can be used in hematopathologic studies.

Adaptor Proteins, Signal Transducing↗

PubMed2005

Expression of the human germinal center-associated lymphoma (HGAL) protein, a new marker of germinal center B-cell derivation.

We identified the human germinal center-associated lymphoma (HGAL) in gene-expression profiling studies of diffuse large B-cell lymphoma (DLBCL). The expression of HGAL correlated with survival in patients with DLBCL. The HGAL gene is the human homolog of M17, a mouse gene expressed specifically in normal germinal center (GC) B cells. We generated a monoclonal antibody against the HGAL protein and show that HGAL is expressed in the cytoplasm of GC lymphocytes and in lymphomas of GC derivation. Among 727 lymphomas tested by immunohistochemistry on tissue microarrays, HGAL staining was found in follicular lymphomas (103 of 107), Burkitt lymphomas (40 of 40), mediastinal large B lymphomas (7 of 8), and in DLBCLs (103 of 151). Most marginal zone lymphomas lacked HGAL staining. Lymphocyte-predominant Hodgkin lymphomas (12 of 17) and, surprisingly, classical Hodgkin lymphomas (78 of 107) were found to be positive. Hierarchical clustering of comparative immunohistologic results in DLBCLs demonstrates that the expression of HGAL is similar to 2 other GC-associated proteins, BCL6 and CD10, but different from 2 markers associated with a non-GC phenotype, MUM1/IRF4 and BCL2. The restricted expression and GC specificity of HGAL protein suggest that it may have an important role in the diagnosis of specific lymphomas, and, potentially in the identification of subtypes associated with different prognoses.

Animals↗

PubMed2005

TMA-Combiner, a simple software tool to permit analysis of replicate cores on tissue microarrays.

We have previously published a suite of software tools that facilitates the reformulation of tissue microarray (TMA) data so that it may be analyzed using techniques originally devised for analysis of cDNA microarray data. However, current microarray data often feature multiple scores for a given tissue sample and antibody combination. Furthermore, an efficient and systematic method for combining scores that takes into account the differing staining properties of tissue epitopes has not been described. We thus present the TMA-Combiner, a new Microsoft Excel-based macro that permits analysis of data for which tissues may have two or more scores per antibody, and permits combination of data from multiple different tissue microarrays. It accomplishes this by rendering one score per tissue per antibody from two or more scores, using one of multiple user-selectable combination rules developed to account for the differing staining properties of tissue epitopes. This greatly facilitates analysis of tissue microarrays, particularly for users with large repositories of data, and may facilitate discovery of biological trends and help refine diagnostic accuracy of tissue markers in clinical samples.

Cluster Analysis↗

PubMed2005

A novel method for making "tissue" microarrays from small numbers of suspension cells.

Tissue microarrays (TMAs) are a highly efficient method for large-scale protein expression studies. To date most TMAs have been constructed using paraffin-embedded specimens. The authors developed a method that allows construction of TMAs from small numbers of cells in suspension. Spun pellets of 1x10 to 1x10 cells are directly processed and embedded in paraffin in an Eppendorf tube. Cylindrical cores of 0.6 mm are taken from these tubes and embedded in a recipient paraffin block to create a TMA. This relatively simple but versatile method enables very small numbers of cells in suspension to be analyzed using the TMA technology and allows for the study of hematolymphoid and related disorders of the blood and bone marrow for which solid tissue samples cannot be readily obtained. With the increasing trend toward obtaining small samples for screening and diagnostic purposes, this method provides a means to manipulate small volume samples for high-throughput immunohistochemical analysis. This method is also amenable for use for cultured cells.

Bone Marrow Cells↗

PubMed2005

Utility of syndecan-1 (CD138) expression in the diagnosis of undifferentiated malignant neoplasms: a tissue microarray study of 1,754 cases.

Syndecan-1, a heparan sulfate-rich membrane glycoprotein, is expressed in plasma cells and is considered a reliable marker of plasmacytic differentiation. However, it has not been widely tested in non-hematolymphoid tissues, and thus its utility in the setting of an undifferentiated malignant neoplasm has not been evaluated. The authors conducted an extensive study of CD138 staining in over 1,700 normal, benign, and malignant non-hematolymphoid tissues, using five tissue microarrays. Immunohistochemical staining was performed with two commercially available CD138 monoclonal antibodies directed against syndecan-1 (Serotec, Oxford, UK, and DAKO, Carpenteria, CA). In addition to the specific membrane staining, many normal tissues and epithelial tumors showed strong cytoplasmic immunoreactivity. A small subset of mesenchymal neoplasms also showed membrane and cytoplasmic immunoreactivity. In squamous cell carcinoma of the head and neck, renal cell carcinoma, and prostate adenocarcinoma, the intensity of CD138 staining inversely correlated with the histologic grade of the carcinoma. However, statistically significant staining differences and their correlation with histologic grades differed depending on whether the Serotec or the DAKO antibody was used. These results indicate that CD138 immunoreactivity is widespread in normal and neoplastic epithelial tissues, as well as a variety of undifferentiated epithelial and mesenchymal processes. The authors conclude that the expression of syndecan-1, although relatively specific to plasma cells within the hematolymphoid system, should be interpreted with extreme caution in the setting of an undifferentiated neoplasm. Furthermore, the two commercially available monoclonal CD138 antibodies tested in this study showed significant differences in their immunoreactivity in different tumor types.

Adult↗

PubMed2005

Follicular dendritic cell immunohistochemical markers in angioimmunoblastic T-cell lymphoma.

Angioimmunoblastic T-cell lymphoma is characterized by a paracortical proliferation of medium to large neoplastic T cells, often with clear cytoplasm, in a background of arborizing high endothelial venules, many surrounded by follicular dendritic cells (FDCs). IHC staining may be applied to highlight these extrafollicular FDCs, traditionally using CD21, or CD23. Several alternative FDC markers have been described, including CNA.42, cystatin A/acid cysteine proteinase inhibitor (ACPI, involved in antigen presentation), and fascin (an actin binding protein). The authors stained a collection of 45 angioimmunoblastic T-cell lymphomas with CD21, CD23, CNA.42, cystatin A, and fascin for direct comparison of FDC staining characteristics in this setting. CD21 highlighted the expected dendritic network of cell processes, within residual follicles and outside of follicles, often adjacent to proliferating vessels. CD23 exhibited similar staining quality but was less sensitive than CD21. CNA.42 showed only diffuse weak labeling of FDCs. Cystatin A stained the cytoplasm of follicular dendritic cells within and outside of follicles; however, staining was often not sharply localized to dendritic cell processes, and scoring was further complicated by reactivity with other cell types in over half of the cases. Likewise, fascin stained a variety of cell types, including strong staining of interdigitating dendritic-like cells, moderate staining of endothelial cells, and only weak staining of follicular dendritic cells within and outside of follicles. Thus, CD21 remains the most reliable marker of follicular dendritic cells in angioimmunoblastic T-cell lymphoma.

Antigens, Surface↗

PubMed2005

Expression of CD163 (hemoglobin scavenger receptor) in normal tissues, lymphomas, carcinomas, and sarcomas is largely restricted to the monocyte/macrophage lineage.

CD163, a hemoglobin scavenger receptor, is expressed in monocytes and macrophages. We tested the expression of the CD163 protein in 1,105 human malignancies and normal tissues using tissue microarrays and conventional paraffin-embedded tissue sections. Besides staining nonneoplastic monocytes and histiocytes (tissue macrophages), membranous/cytoplasmic staining for CD163 was primarily limited to neoplasms with monocytic/histiocytic differentiation. CD163 reactivity was not observed in normal tissues, lymphomas, carcinomas, and in a majority of mesenchymal neoplasms, including follicular dendritic cell tumors (0 of 4), although it stained admixed histiocytes. Staining for CD163 was seen in Rosai-Dorfman disease (5 of 6), histiocytic sarcoma (3 of 4), littoral cell angioma (6 of 6), and Langerhans cell histiocytosis (3 of 5). A subset of atypical fibrous histiocytomas (9 of 16), benign fibrous histiocytomas (6 of 9), and atypical fibroxanthomas (1 of 3) also showed CD163 staining. Our studies also confirm earlier work showing that CD163 is expressed in acute myeloid leukemia with monocytic differentiation (AML, FAB subtype M5) (2 of 6), as well as a majority of giant cell tenosynovial tumors (7 of 8). Its limited range of expression and tissue specificity indicate that CD163 may have significant diagnostic utility in separating specific tumors with monocytic and histiocytic derivation from other entities in their differential diagnosis.

Antigens, CD↗

PubMed2005

Expression of the bcl-6 and MUM1/IRF4 proteins correlate with overall and disease-specific survival in patients with primary cutaneous large B-cell lymphoma: a tissue microarray study.

BACKGROUND: Systemic B-cell lymphomas have been studied using microarrays, which has led to a better understanding of their molecular characteristics. Initial microarray studies of these lymphomas have implicated several genes as important predictors of outcome. In this study, we used a tissue microarray (TMA) to characterize primary cutaneous large B-cell lymphomas (PCLBCL). METHODS: We studied 14 patients for whom clinical follow up was available, including four patients whose lesions were limited to the leg on presentation. Immunohistochemical staining with CD20, CD44, CD21, CD5, CD10, bcl-2, bcl-6, Ki67, p53, and multiple myeloma 1 (MUM1) was examined. RESULTS: Our results identify two subgroups of lymphomas. The first group showed staining with bcl-6 and had an overall survival of 176 months (p = 0.003). The majority of this group was negative for MUM1. The second group lacked staining with bcl-6 and had an overall survival of 26 months, with a majority of these cases staining with MUM1. Three of four patients with PCLBCL of the leg showed no staining with bcl-6. CONCLUSIONS: Our study demonstrates the utility of TMAs in the analysis of PCLBCL and that expression of bcl-6 and MUM1 correlates with survival.

Adult↗

PubMed2005

The NFATc1 transcription factor is widely expressed in white cells and translocates from the cytoplasm to the nucleus in a subset of human lymphomas.

Stimulation of lymphoid cells via their surface receptors triggers signalling pathways that terminate in the nucleus, where they induce alterations in gene transcription. Nuclear factor of activated T cells (NFAT) transcription factors, involved in a major Ca2+-dependent signalling pathway, normally reside in the cytoplasm but re-locate to the nucleus when activation of the pathway (e.g. following ligation of antigen receptors) leads to their dephosphorylation. This study found that one member of the NFAT family (NFATc1/NFAT2) can be detected in routine biopsy samples, where it is seen in essentially all lymphoid cells, but is absent from the great majority of non-haematopoietic cells. An immunohistological evaluation of NFATc1 in almost 300 lymphomas showed that most neoplastic lymphoid cells also express NFATc1 as a cytoplasmic constituent, although it is absent in classical Hodgkin's disease and plasma cell proliferations. Of particular interest was the finding that NFATc1 was relocated to the nucleus in a minority of lymphoid neoplasms (usually diffuse large B-cell lymphomas or Burkitt lymphoma), presumably reflecting activation of the NFAT pathway. It would be of interest to correlate this feature with patterns of gene expression and also with prognosis, since it may identify a subset of human lymphoma that is distinct in its molecular and clinical features.

Biomarkers, Tumor↗

PubMed2004

Immunophenotypic and genotypic characterization of progression in follicular lymphomas.

Progression of follicular lymphomas (FLs) is often accompanied by a spectrum of histologic changes and an aggressive clinical course. Although molecular alterations have been implicated in this event, the underlying factors are largely unknown. We studied the expression of selected tumor suppressor genes (P53 and retinoblastoma [RB]), oncogenes (MYC and BCL2), and a transferrin-receptor related protein (Trump) in sequential biopsies in 16 patients. Eleven patients progressed from grade I or II FL to aggressive B-cell lymphomas with diffuse morphology, whereas 5 patients presented with diffuse aggressive lymphomas and recurred with indolent lymphomas. Immunoreactivity for P53 correlated with higher histologic grade in lymphomas progressing from indolent to aggressive; however, only 1 patient who presented with aggressive lymphoma demonstrated a P53 gene mutation. Neither P53 immunoreactivity nor genotypic alterations correlated with presentation with an aggressive histology and relapse with FL. Growth fraction, as assessed by Ki-67 staining, and Trump expression correlated with histologic grade. Immunoreactivity for RB, BCL2, and MYC was seldom associated with progression. Eight of 9 cases tested exhibited identical immunoglobulin heavy and light chain rearrangements or identical BCL2 gene rearrangements in the sequential lymphomas. We conclude that P53 and Trump protein expression and proliferation activity correlate with histologic grade, but not with recurrence or progression of FL. Our results further indicate that progression of FL to diffuse aggressive lymphomas and presentation of an aggressive B-cell lymphoma followed by FL are clonally related.

Antigens, Neoplasm↗